Recent Workers Research Articles

A note on the Cause of Certain Red Colorations on Salted Hides and a Comparison of the Growth and Survival of Halophilic or Salt-loving Organisms and Some Ordinary Organisms of Dirt and Putrefaction on Media of Varying Salt Concentrations

Hides and calf skins cured with marine salts, especially if kept under conditions of warmth and moisture, tend to develop on the flesh side large areas of brick-red coloration. Similar red colorations have, for many years, been noted as occurring in similar conditions on salted fish, and a number of investigations have been made as to their cause, the first recorded being that of Farlow (1878). Following him were Mauriac (1886), Ewart (1887), Layet (1887), Le Dantec (1891) and, in recent years, Harrison and Kennedy (1922), Browne (1921–22) and Cloake (1923). All these workers have agreed in attributing the red coloration on salted fish to the growth of one or several species of redcoloured organisms, and the more recent workers (Harrison and Kennedy, Browne, Cloake) trace these organisms to the sea salt used in curing the fish, and find them to be chromogenic bacteria only capable of growth in a high concentration of salt. Clayton and Gibbs (1927) have examined many solar brines and salts, and have found that “they almost invariably contain microorganisms which only exist and develop in the presence of abundance of common salt.” Sturges and Heidemann (1923, 1924) have isolated many saltloving organisms from meat-curing solutions, and Le Fèvre and Round (1919) from the brine of pickled cucumber.

The development and vascularisation of the corpus luteum in the mouse and rabbit

The development of the corpus luteum from the ruptured follicle has been the subject of a very large number of memoirs. Of these the most important have been summarised by Van der Stricht (1912) up to 1912 and more recently by Hill and Gatenby (1926) and Corner (1919), so that no useful purpose would be served by recapitulating in detail the controversial discussions contained in them. Many of the older papers are not based on a complete series of early stages of early stages of corpora lutea, since either the material was not available, or else the writers were unable to diagnose accurately the time of œstus. Sobotta (1890, 1897), Cohn (1903), Marshall (1904, 1925), and van der Stricht 91912), however, drew their conclusions from a series of accurately dated ovaries, as have more recent workers (Cornern 1919; Drips, 1919; Hill and Gatenby, 1926; Kurashige, 1927; Long and Evans, 1922; and Watrin, 1924). It is now generally agreed-and has been shown conclusively in the work of Hill and Gatenby (1926)-that the lutein cells are formed by the enlargement of the follicullar epithelium. The fate of the theca interna cells, which surround the mature follicle prior to ovulation, is still a matter of dispute, and the problem is complicated by histological species differences. There seems no reasonable doubt, however, that these elements take part in the formation of the corpus luteum, since, in numerous cases, the typical fat containing cells, closely associated with the vascular connective tissue, can be distiguished among the follicular lutein cells after ovulation. It remains to be decided whether or not they persist as functional elements, and retain their individuality.

Some Experiments with Suggestion and Association Tests in the Feeble-Minded

When I was asked to either open a discussion or read a paper, I felt a great difficulty in choosing a subject, and I think my choice has been influenced considerably by the interest shown by the public in mental defect. Probably all of us are conversant with some of the various methods that are in use for testing the intelligence. These appear to resolve themselves into either valuing or “marking” by plus or minus or using numbers. It has always appeared to me that in marking by plus or minus signs it is very difficult to form an opinion as to whether it should be + ! or + ?, whereas it is easier to use figures. For instance, you say to a child, “What is the difference between an orange and a banana?” and you desire two comparisons to be given. If you give one mark for a definite comparison and no marks for an indefinite comparison it appears fairly simple, whereas if you are marking by the plus signs and one comparison is correct and the other wrong, it appears to me to be difficult to tell which of the plus signs one should use in marking the whole result. I therefore use the point scale test of Yerkes and Bridges. This method, with some slight modifications of my own, I and my colleagues have used in all the cases. I do not believe that a child cannot be tested until it has reached the age of five years. In this I have some support from recent American workers, and a method of testing the young child may yet be devised. Therefore in marking I do not, as Yerkes and Bridges do, start from five years of age, but as though the child could think from birth. The two tests which I hope to discuss at this meeting are those of association and suggestion. These two units appear to offer some interesting theories which might be worthy of further investigation. In a sense these two tests are dependent on each other psychologically and throw some light on the elucidation of some of our problems, and may perhaps enable us to form deductions of some diagnostic and prognostic value.

Effect of Therapeutic Venous Ligation on Blood Flow in Cases of Arterial Occlusion.

That the incidence of gangrene in a healthy extremity, whose main arterial supply has been suddenly interrupted, is reduced by the simultaneous or early obstruction of the concomitant or proximal venous return has been demonstrated repeatedly by clinical and experimental observers. The physiological explanation of this phenomenon, however, is in part still the subject of controversy. It is recognized by all recent workers that ligation of the venous return causes an increase in the blood pressure of the affected extremity. Opinions as to its effect upon the flow of blood, however, differ widely. Brooks and Martin believe that this procedure decreases the blood flow, while Holman and Edwards maintain that the blood supply is increased. Neither of these 2 groups of workers measured the flow of blood directly. Recently there has been devised in our laboratory a direct, continuous volume flow apparatus, a modification of the Ludwig stromuhr and of Stolnikow's double inlet-outlet apparatus, which is controlled by an electrically regulated valve. By means of this instrument we have measured directly the changes in blood flow to an extremity, resulting from ligation of its principal peripheral arterial supply and venous return. A preliminary report on this work forms the basis of this paper. Male dogs, weighing 13 to 17 kg. were anesthetized by the intravenous injection of 200 mg. per kg. of sodium barbital. Coagulation was prevented by 30 mg. of heparin per kg. The volume flow apparatus was placed in the right iliac artery, thus measuring the blood which entered the right femoral artery as well as the chief collateral arterial supply to the right leg. The systemic blood pressure was taken from one of the carotid arteries. The right superficial femoral artery and the right common iliac vein were exposed to permit ligation.

OVARIAN RESPONSES

Attention has been directed recently toward human urine as a source of supply of several hormonal substances. Aschheim and Zondek1reported constant and characteristic responses in the ovary of the immature mouse to injection of the whole urine of pregnancy which they have ascribed to a hormone of the anterior lobe. Louria and Rosenzweig2have reported similar results. It is not to be denied that the urine from pregnant women elicits an ovarian response similar in some respects to that induced by implants of the fresh anterior lobe. Other features of this response, however, differ greatly from those produced by the fresh gland. It is to these atypical features which appear not to have been appreciated by recent workers in this field, and which make untenable their assumption that this is a typical anterior pituitary response, that attention is called here. In the present experiments, immature mice, from

A Quantitative Investigation of the Efficiency of Instruction in High School Physics

Quantitative investigations in measuring school products have be come a distinctive feature of the more recent activities in the educational field. These investigations conducted in all the elementary school sub jects, which now have passed the experimental stage, have turned the attention of recent research workers to the need of objective devices for the measurement of attainments in high-school subjects. In the past, the examination system has been used as a test of the individual performance of pupils. The teachers prepared the examina tion questions and were the sole authority in grading the papers and assigning values. Under such a system, the teachers had no basis for the evaluation of the performance of their students as compared with the work of other students. In recent years there has been a revolt against this method of inaccurate measurement of school achievement, which has always been expressed in terms of school marks. This criti cism has not been directed so much against the marking system as against improper methods of marking. In fact there has never been a system, but rather a practice which was neither systematic nor scientific.

Radio Transmission Formulae

A radio transmission formula is derived by summing the fields due to an infinite number of reflected waves. The problem is rigorously solved for two parallel infinitely conducting planes, and an approximate solution is obtained for two concentric conducting spheres of finite conductivity. The results thus obtained are found to be in accord with those obtained by G. N. Watson in 1919 by the use of spherical and zonal harmonics. The method here employed approximates much more closely to the point of view adopted by recent workers in the radio field and adapts itself more readily to a study of gradually varying boundaries. A modification in the coefficient of the exponential term in the Austin long wave radio transmission formula which alters it from $(\frac{120\ensuremath{\pi}\mathrm{lI}}{\ensuremath{\lambda}\ensuremath{\rho}}){(\frac{\ensuremath{\theta}}{sin\ensuremath{\theta})})}^{\frac{1}{2}}\mathrm{exp}[\ensuremath{-}\frac{0.0015\ensuremath{\rho}}{{\ensuremath{\lambda}}^{\frac{1}{2}}}]$ to $(\frac{120\ensuremath{\pi}\mathrm{lI}}{\ensuremath{\lambda}}){(\frac{3\ensuremath{\pi}\ensuremath{\theta}}{8phsin\ensuremath{\theta}})}^{\frac{1}{2}}\mathrm{exp}[\ensuremath{-}\frac{0.0015\ensuremath{\rho}}{{\ensuremath{\lambda}}^{\frac{1}{2}}}]$ is suggested by the analysis and a theoretical justification for the ${\ensuremath{\lambda}}^{\ensuremath{-}\frac{1}{2}}$ in the exponent for the case of long wave transmission is emphasized. The results obtained by the application of the modified formula to the long wave transmission data obtained by Guierre is discussed and an improvement in the agreement found.

HOST SUSCEPTIBILITY TO TYPHOID, DYSENTERY, FOOD POISONING AND DIARRHEA

One of the notable achievements in preventive medicine has been the control of the communicable diseases spread largely through alvine discharges. This has been accomplished by limiting the distribution of the typhoid bacillus by sanitary measures and, to a lesser extent in the civilian population, by specific prophylactic immunization. My purpose in this communication is to call attention to certain new factors that influence the distribution of bacteria in alvine discharges, and, what is even of greater importance, changes in the susceptibility of the host due to disturbances of the normal gastro-intestinal functional activities. The acidity of the gastric contents acts as a barrier to the passage of viable bacteria into the small intestine. Recent workers have shown that this is not a trustworthy germicidal agent under ordinary circumstances.1Bacteria introduced directly into the duodenum are usually killed before reaching the large intestine. Arnold and Brody2have recently

Occurrence of Extensor Rigidity in Quadrupeds as a Result of Cortical Injury

PERMANENT contraction of certain muscle groups occurs in apes, following the removal of the cortical motor centres of the limbs. Hermann Munk (1895) stated that ‘contractures’ do not occur in rabbits, cats, and dogs following similar operations. Recent workers are of the opinion that extirpation of the gyrus proreus of the cat results in an exaggerated extensor tonus in the contralateral limbs, but removal of the motor cortex fails to influence the tonus of the corresponding limbs.

The Quantitative Biological Effects of X-Rays of Different Wave-Lengths

The relative effectiveness of X-ray beams having equal intensity but different wave-lengths has been a subject of study for many years. It is now generally believed that both hard and soft rays produce the same kind of morphological change in living cells; but whether the amount of such changes varies with the quality of the beam is still a debated question. That the quantitative effects increase with increasing wave-length is believed by Dessauer,1 Russ,2 and Wintz and Rump,3 to mention only a few of the more recent workers. Others hold that the relation is not as simple as this. Meyer and Glasser4 find that while in general the above relation obtains for the range of wave-lengths ordinarily employed in therapy, it does not hold true for very soft rays, for these show a decreasing activity. The maximum efficiency is found in a beam having the quality corresponding to a half value in 2 mm. of aluminum. A view practically the reverse of this is held by Dognon.5 In his experiments with Ascaris eggs he finds that a homogeneous beam having a wave-length of 0.70 AU. produces smaller effects than beams composed of rays longer or shorter than this. A third view is that of Wood,6,7 Arntzen and Krebs,8 and Holthusen,9 who state that within certain limits, the quality of the beam makes no difference with the effectiveness of the rays. According to the latter workers, therefore, dosage can be adequately expressed in terms of electrostatic units, that is, by stating the intensity of the beam and the duration of exposure; while the former hold that both intensity and effective wave-length must be considered.

MONILIA INFECTION OF THE TONGUE

Since Robin in 1853 named the thrush fungus<i>Oidium albicans</i>, there has been a continuous controversy as to the botanic position of this parasite. The chief ground for dispute appears to be the fact that growth on some artificial mediums takes place as a yeastlike form and on others as long branching mycelia similar to the morphology of the molds. Recent workers have shown by more accurate measures that ascospores are absent, and by utilizing fermentation tests, agglutination reactions and experimental inoculations, have demonstrated that the thrush parasite should not be included among the oidia or saccharomyces, but that it belongs to the monilia family (Hansen, Reess and others). The term<i>Monilia</i>, as understood today by mycologists, has been extended chiefly by the researches of Castellani and Pinoy to include every yeastlike organism which forms mycelia, even in small amounts, but no ascospores on certain mediums. For practical purposes, Castellani

THE GROWTH OF THE LONG BONES IN CHILDHOOD

INTRODUCTION The mainspring of medical research is the interpretation of the phenomena of disease in terms of disordered physiology. The widest gap in the search for this interpretation is seen in diseases of the bony, muscular and blood vascular systems. The innumerable systems of classifying diseases of bone, teeth, muscle and blood vessels indicate that either the clinical and pathologic data or the normal developmental processes have not been elucidated. Our knowledge of the anatomy and physiology of bone is limited. On the one hand, little is known of the nerve supply and lymphatic supply of this tissue. Attempts to interpret the function of the periosteum have produced a series of conflicting views from Hunter 1 and Duhamel, 2 Cheselden and Haller, Ranvier and Sharpey to Tillier, Macewen 3 and Gallie and Robertson. 4 The origin of the osteoblast is still undecided, though recent workers such as Stump 5 and Fell 6 tend to regard the

Histoplasmosis of Darling

SummaryHistoplasmosis of man has been known hitherto only from the three cases reported by Darling, from Panama.A fourth case is here reported—that of a woman who had not been out of the State of Minnesota in forty-two years.The case was clinically identical with those reported by Darling: greatly enlarged spleen, pseudo-granuloma of the lungs, emaciation, and anemia.In phagocytic cells of the lung, liver, spleen, and lymph nodes were enormous numbers of the organism described by Darling under the name Histoplasma capsulatum.As pointed out by da Rocha Lima (1912) this organism is evidently closely related to Cryptococcus farciminosus Rivolta, the cause of epizootic lymphangitis of horses and man. While da Rocha Lima and most recent workers regard this organism as a yeast, Ota (1925) places it in the genus Grubyella, among the Hyphomycetes. Most of the mycoses which become systemic are rapidly fatal. This condition was systemic and chronic for many years.The available evidence does not support the view that histoplasmosis of man is identical with epizootic lymphangitis.In clinical picture and in size and morphology of the organisms it differs from the torulosis of Stoddard and Cutler, cases of which have been noted especially in the vicinity of Chicago, Illinois.The probability is that in histoplasmosis and in epizootic lymphangitis we are dealing with two very closely related species of Cryptococcus (Grubyella), one causing systemic infection and one largely superficial. An analogous situation is afforded by Leishmania donovani and Leishmania tropica.The finding of this case emphasizes the importance of considering the possibilities of the disease in connection with obscure cases of splenomegaly in temperate as well as in tropical zones.

Minute “Organisms” isolated from the Virus of Mosaic Disease of Tomato

THE nature of the infective principle in plants suffering from mosaic disease is obscure, although most recent workers favour the view that it is a living organism. Allard and Duggar have emphasised the minuteness of the causal agent, whilst Matz, Kunkel, Nelson, and others have described protozoan - like bodies in the cells of affected plants.

STUDIES ON THE POTASSIUM CONTENT OF HUMAN SERUM

OBSERVATIONS OF OTHER WORKERS The normal potassium content of the human blood serum has been determined by different workers with various results, as shown in Table 1. The older writers, Schmidt and Wanach, worked with inferior chemical methods. The more recent workers have all obtained fairly uniform results with the exception of Richter-Quittner whose figures are considerably higher than those reported by others. Richter-Quittner found the concentration of potassium in ashed serum to be considerably higher than that found in the ultrafiltrate from the same serum. He argued from this that a portion of the potassium was bound to serum protein. Kramer and Tisdall, however, have found no discrepancy between the results obtained on ashed serum and those by direct precipitation from the same serum. 7 They have emphasized the remarkable constancy of the concentration of potassium in normal human serum. A number of investigators have studied the potassium of the serum in pathologic conditions.

On the intravascular development of erythrocytes in the bone marrow of the adult pigeon

The observations of Maximow and Danchakoff in fixed tissue, and of Sabin in the living blastoderm, have demonstrated that the red blood cells differentiate intravascularly in the embryo. Maximow and others have contended that the adult bone marrow differs from the embryological vascular areas in the method of producing red cells. They believe that, in adult marrow, the erythrocytes develops in extravascular clumps, the mature cells later making their way into the bloodstream. This has been so generally accepted that most recent workers have concentrated on attempting to determine the mechanism whereby the adult erythrocytes obtain entrance to the circulation. In studies on the vascular pattern of the pigeon's marrow with an hypolasia induced experimentally by starvation, an extensive system of intersinusoidal, collapsed capillaries lined by an embryological type of endothelium was observed for the first time. These capillaries, evidently, are not normally patent to the circulating blood as are the transition capillaries which connect arterioles and venous sinuses. The cellular elements in the hypoplastic marrow are reduced to three types: fat cells, reticular cells, and endothelial cells; and the depleted cellular structure of the marrow is replaced by an increase of fat deposit. The hypoplastic marrow of the starved animal recovers rapidly upon the resumption of an ordinary diet thus providing a simple physiological method of experimental control without the introduction of any complicating factors. When feeding is resumed and observations are made at varying intervals thereafter, it is possible to secure a series of marrows of various degrees of complexity, as normal cellularity is approached. An analysis of each stage, from the simple depleted to the normally cellular state, enables a clarity of interpretation and understanding of the normal process of blood-cell formation and development hitherto unknown.

Biology of Mosquitoes and the Disappearance of Malaria in Denmark

AN interesting memoir on the biology of Danish Culicidas has recently been completed by Dr. C. Wesenberg-Lund (Mem. Acad. Roy. Sc. et Lettres de Danemark, Section des Sciences, Series 8, vol. 7, No. 1, 1921). Forty forest-ponds were subjected to regular fortnightly exploration for some years, and from them twenty-five species have been obtained, twenty of which have been reared from larvæ. Among these are four species of Ochlerotatus known from America, but not hitherto found in Europe. Observations on the habits of the larvae lead the author. to support the general conclusion reached by other recent workers that the anal gills are best developed in those larvas which feed at the bottom of the water. The pupæ are, as every one knows, capable of movement, but they are much more stationary than is usually believed; indeed, the author goes so far as to say that usually there is no locomotion during the whole of the pupal stage. An attempt has been made to work out the life-history of each species of Culicine from the laying of the egg onwards, and the author records many interesting observations. For instance, Ochlerotatus communis was found to lay its eggs singly on withered leaves or on the ground under neath these; the eggs are hatched in midwinter or early spring—many of them in April—and the imagines emerge in the first half of May. Mating takes place shortly afterwards, but the craving for blood does not arise until the latter part of June. Eggs are deposited upon dry bottoms from August to December, but do not hatch until they have passed through a period of frost. The biology of Taeniorhynchus Richardii also presents features of special interest; the siphon of the larva pierces the submerged roots of aquatic plants and gains access to the air in the intercellular spaces; the siphons of the pupas are brought into close apposition at their tips and are inserted into submerged roots.

Studies on synapsis. III.—The nuclear organisation of the gern cells in Libellula depressa

An impressive array of facts in support of the chromosome hypothesis has been elucidated by the researches of cytologists during the past two decades; nevertheless the paucity of direct objective evidence for the integral continuity of the chromosomes through all stages of nuclear history still presents a barrier to unqualified acceptance of its validity. Such knowledge is not only essential to a convincing presentment of the chromosome hypothesis: it has furthermore a very intimate bearing upon the interpretation of synapsis. The earlier workers, following Flemming, interpreted the prophase and telophase organisation of the nucleus as a continuous spireme: this notion rapidly hardened into a dogma, which not only handicapped further inquiry into the problem of the constitution of the resting nucleus, but proved to be a source of much confusion respecting the significance of the events in the meiotic phase. How far theory even succeeded in overriding fact may be illustrated sufficiently by a quotation from a paper that has exerted a powerful influence on cytological theory. In reference to the spermatogonial prophases of Periplaneta, the authors state correctly, "the method of chromosome formation here depicted presents nothing exactly comparable to the long spireme thread which is figured in so many existing accounts of the premeiotic divisions." After this unequivocal statement the interpretation given to account for the reduction of the chromosomes is that "the spireme threadwork tends to separate out into half as many lengths" as the number of premeiotic chromosomes. Now, it may safely be said that in general (as well as in the case of Periplaneta) recent research has fully justified Bolles Lee in his contention that "ni à la télophase, ni aux prophases, ni à aucun moment de l'existence de ces noyaux, il y aît formation d'un spiréme continu." Yet even recent workers, like Arnold, 1909 (1), Nakahara, 1919 and Harman, 1920 (2), in their inability to account for telosynaptic union by other means, fall back upon the conception of a spireme segmenting into the haploid number of threads as a means of effecting reduction.

A Contribution to the Study of Meningococci

It has been shown by numerous observers that well-marked serological differences are found between different strains of meningococci. And since the work of Dopter on the relation of “parameningococci” to meningococci and to cerebro-spinal fever, there has arisen a fairly general agreement that among meningococci capable of causing cerebrospinal meningitis two broadly separable groups can be defined by immunological methods. But beyond this point considerable divergences of opinion appear. On the one hand there are a number of recent workers who have failed to convince themselves that the two groups of meningococci are in reality clearly delimited, permanent and independent entities. On the other hand certain other workers claim to have still further subdivided these micro-organisms into four definite and independent types, each of which possesses in itself the value of a bacterial species [cp. Andrewes (1917)].

Acanthocephala of the Subfamily Rhadinorhynchinae from American Fish

But two species of Acanthocephala have, to the present time, been definitely ascribed to the genus Rhadinorhynchus. Echinorhynchus pristis Rud. was the original species for which Liihe (1911) created this genus. One year later he added another species to the genus by his description of R. horridus from Egypt. The older species has been reported as parasitic in fishes from various parts of the world. The descriptions given in these scattered reports differ so radically that it seems improbable that they could all apply to single species. Here, as in other genera of Acanthocephala, it seems obvious that the older workers, recognizing the cardinal points which in modern classification have been accepted as indicative of generic value, have failed to observe the less obvious, though significant, differences which serve to separate species. Thus all members of the present genus Rhadinorhynchus have been identified as E. pristis, and the descriptions have usually been inadequate to enable more recent workers to recognize the same forms if encountered again. In some few instances the descriptions have been complete enough to permit one to recognize the forms described. Linton's work on E. pristis is of the type last mentioned. In 1891 Linton recorded the occurrence of Acanthocephala which were at least similar to E. pristis from the intestine of Tylosurus acus (Lacep), and of Lobotes surinamensis (Bloch). After acknowledging perplexity in attempting their identification, Linton tentatively ascribed some of his individuals to the species E. pristis, while others he referred to new variety of that species. To the variety he gave the name E. pristis tenuicornis. In later work he remarked upon the presence in what he determined as E. pristis from fishes at Beaufort, N. C., of a of at the base of the proboscis which are longer than the other hooks (Linton, 1908:89). This circle of was briefly mentioned in an earlier paper (1892:531). In materials studied by the present writer, the spines at the base of the proboscis, though not forming circle, are very conspicuous. After comparison of these specimens with data given by Linton the writer is convinced that Linton was at various times dealing with at least two distinct species of the genus Rhadinorhynchus to which he gave