Normal Frog Research Articles

Influence of radium and x-rays on the frog's leucocytes

The white blood corpuscles are the most sensitive cells to the action of radium and x-rays. The senior writer has indicated in his previous publications that this action differs specifically for the various types of the white blood cells. This “selective” biological action of the rays goes even beyond the apparent structural differences of the cells. The rays for instance destroy rapidly the lymphocytes of lymphatic leukemia, while they have a comparatively slight effect on the lymphocytes in conditions of inflammatory leucocytosis. As a general rule the result of the action of radium and x-rays on the normal blood consists in the diminution of the number of lymphocytes and a relative increase in the number of the polymorphonuclear leucocytes. The other types of leucocytes usually remain unaffected. The real significance of this phenomenon will remain obscured until a clearer insight is gained into the derivation and the comparative functional significance of the two types of white blood cells. The numerical proportion of the lymphocytes and the polymorphonuclear leucocytes differs in the various animal species and it is therefore of great importance for the ultimate elucidation of the whole problem to test the action of the rays on different species of animals. The present investigation consisted in subjecting to the action of radium and x-rays normal frogs and also frogs in whom a change in the white blood cells was induced by a preliminary injection of yeast. X-raying of Normal Frogs.—The method consisted in taking a total and differential blood count of the animal before the raying. The whole animal was then x-rayed (45 minutes, Coolidge tube, 7 ma. 9-inch spark gap, 5-inch focal distance) and blood counts taken at various intervals for four days.

On the reaction of the pigment cells in normal and albinous frog larvae

In the experimentally produced albinous frog larvæ which follow a successful early extirpation of the epithelial portion of the hypophysis, a pigmentary system is produced which is not only strikingly different from the normal in its anatomical and physiological condition but also exhibits striking departures from the normal in its physiological responses. Normal larvæ kept in diffuse light and on an indifferent background usually show a fully expanded, or only slightly contracted, condition of the epidermal melanophores1 and a completely contracted, or but slightly expanded, condition of the corial xantholeucophores. This condition can almost always be somewhat exaggerated by submitting the larvæ to the simultaneous action of low temperature and darkness, when the epidermal pigment cells are fully expanded and the corial xantholeucophores minute, silvery dots. When such larvz, or those from an indifferent environment, are submitted to reverse conditions, i. e., the simultaneous action of warmth (33°-35° C.) and sunlight, these two classes of pigment cells react in the reverse way and in from one half to one hour exhibit a picture of contracted melanophores and widely expanded silver cells. It is thus seen that the reactions of the two groups of superficial pigment cells-the epidermal melanophores and the corial xantholeucophores-go hand in hand and are in a reverse direction. Attention has already been called to the constant great expansbn of the corial xantholeucophores in the albinos, an expansion which exceeds considerably that which can ever be obtained by the action of sunlight and heat on normal larvz Moreever, it is difficult to influence by physiological means this great expansion of the xantholeucophores in the albino. On the other hand, the epidermal melanophores of the albinos, which exhibit various stages of contraction, are widely expanded by the action of heat and light, an effect just the opposite of that which the same factors produce in the normal skin.

Studies on the relation of iodin to the thyroid. II. Comparison of the thyroid glands of iodin‐fed and normal frog larvae

Journal of Experimental ZoologyVolume 27, Issue 3 p. 417-425 Article Studies on the relation of iodin to the thyroid.† II. Comparison of the thyroid glands of iodin-fed and normal frog larvae W. W. Swingle, W. W. Swingle Fellow in Biology, Princeton UniversitySearch for more papers by this author W. W. Swingle, W. W. Swingle Fellow in Biology, Princeton UniversitySearch for more papers by this author First published: January 1919 https://doi.org/10.1002/jez.1400270307Citations: 5 † The experimental work for this paper was done while the writer was instructor in zoology at the University of Kansas. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume27, Issue3January 1919Pages 417-425 RelatedInformation

IODIN AS THE ACTIVE PRINCIPLE OF THE THYROID GLAND

The relation of iodin to the thyroid gland has been for many years a matter of great interest to clinicians and experimentalists, and it has long been recognized that this substance holds an important place among the constituents of the gland. For several years the writer has been engaged in research on problems involving the thyroid, and this last spring obtained some results in the course of a series of iodin-feeding experiments which should prove of interest to clinicians and other readers of this magazine. The complete account of these experiments has appeared elsewhere (Jour. of Exp. Zoology, Abstracts, Endocrin, 1918, 2, 200, hence only a summary will be given here. The problem briefly stated was to test the relation of iodin to the physiological activity of the thyroid and the general problem of amphibian metamorphosis, by feeding this substance and various of its compounds to normal and thyroidless frog larvae.

The influence of decerebration on the convulsant action of caffein in frogs

It is well-known that destruction of the brain causes increase of reflex action in frogs, especially when they are kept in the cold, and last year I reported that the effect of morphin, which causes in frogs tetanus indistinguishable from that of strychnin, was very markedly increased by decerebration, the effective dose in such frogs being about one tenth of that in normal frogs. I wish to report now on the result of a study of the effect of decerebration upon the convulsant action of caffein. Caffein salts which are strongly acid cause a peculiar muscular stiffness which masks the central action. The alkaloid itself causes also a certain muscular stiffness but it is much less marked and is only troublesome with large doses. The alkaloid was therefore used in these experiments. As was the case with other convulsant drugs we found the action of caffein much greater in the cold. If the frogs are kept cold tetanus can be obtained with doses which are too low to markedly affect the muscles. In contrast to morphin we found that both in the cold (2-5° C.) and in the warm (12-18° C.) there was no difference between normal and decerebrate frogs in their response to the convulsant action of caffein. In both tetanus was obtained in the cold in all frogs with doses of 0.2 mg. p. gm. and in most frogs with 0.1 mg. p. gm. At room temperature tetanus was constantly obtained in normal decerebrate frogs with doses of 0.6 mg. p. gm. but never in either with 0.3 mg. p. gm. The experiments show that there is a difference of some sort between the actions of caffein and morphin on the central nervous system although the convulsions are identical in appearance.

The convulsant action of strychnin and morphin in cardiectomized frogs after destruction of the anterior lymph hearts

Meltzer has shown several years ago that in cardiectomized frogs strychnin causes convulsions nearly as well as in normal frogs and morphin causes convulsions even a good deal sooner and with smaller doses. We have shown later that low temperature is an important factor in the success of these experiments. About a year and a half ago, Abel, while admitting the facts, made the statement that the success in these experiments depends upon the activity of the anterior lymph hearts. At the meeting of December, 1912, Meltzer demonstrated cardiectomized frogs with destroyed lymph hearts in strychnin convulsions. The method of complete evisceration employed in these experiments produced, however, such a complete shock that there was a success only in a certain percentage of the experiments. We now employed another method. After destruction of the anterior lymph hearts in normal anesthetized frogs, the animals are permitted to fully recover from the anesthetic and the operation, and the blood heart is removed either a few hours later on the same day or next day. The success is now nearly 100 per cent. The animals have, of course, to be kept at a fairly low temperature. The success is now positive although practically all the injections are made now in the lymph sacs surrounding the thigh and the solution has to travel a longer distance before it reaches the upper end of the cord. You see here frogs in strong tetanus which received strychnin or morphin several hours ago. After evisceration you can see now that the anterior lymph hearts were destroyed. It is evident that the anterior lymph hearts have nothing to do with the convulsive action of strychnin and morphin in cardiectomized frogs.

Decerebration and the action of morphine in frogs

Morphin given in sufficient dose to normal frogs causes tetanus which does not come on, however, until several hours or even days after the injection. I have found that decerebration hastens the onset of tetanus and also causes a marked reduction in the amount of morphin required to induce tetanus. The smallest dose with which tetanus can be induced regularly in normal frogs at room temperature is 1/3 of a milligram per gm. (10 milligrams for a 30 gm. frog). This tetanus comes on in about 24 hours. In decerebrated frogs, at room temperature, tetanus comes on after such a dose in from 1/2 to 6 hours, and may be induced with certainty after 6 to 24 hours by a dose of 1/10 milligram per gram (3 mg. for a 30 gram frog). When frogs are kept cold tetanus can be induced by much smaller doses, as we have stated in an earlier paper. Thus, intact frogs kept in the cold show tetanus after doses of 1/30 mg. per gm. (1 milligram for a 30 gram frog). Tetanus comes on after such a dose in from 18 to 24 hours. Decerebrated frogs show tetanus after such a dose in from 4 to 12 hours, and it may be induced with certainty by doses of 1/300 milligram per gm. (1/10 mg. for a 30 gm. frog) after an interval of 1 to 3 days. Frogs with the entire brain including the medulla destroyed, do not respond as well as frogs with the entire brain except the medulla destroyed.

THE DISTRIBUTION OF SOLUTIONS IN CARDIECTOMIZED FROGS

Strychnin and adrenalin when injected into cardiectomized frogs are efficiently distributed all over the animal body and when administered in sufficient quantities produce the usual reactions of these alkaloids. The experiments with strychnin prove positively that the paralysing effect of this poison is due to its direct action upon the nerve cells of the cord, and not, as Verworn assumes, to a paralysing action upon the heart. When morphin is injected into cardiectomized frogs the effects are much greater and incomparably more rapid than when administered to a normal frog. The normal circulation probably contains substances derived from some organs capable of modifying and retarding the specific effects of morphin. The distribution of solutions in animals deprived of their circulatory apparatus takes place through the tissue spaces, which present a more or less well connected system of communications throughout the entire animal body, especially through its peripheral parts. This mode of distribution is designated as the peripheral mechanism. In contrast to the centralizing cardiovascular apparatus, the peripheral mechanism permits a greater autonomous action of organs and a more localising effect of injections. The peripheral mechanism found to be active in animals deprived of their circulation is probably identical with the mechanism which serves for distribution of the mesolymph in living animals not yet possessing a circulatory apparatus. The existence of the peripheral mechanism in animals with a cardiovascular apparatus possesses probably a phylogenetic significance. It is assumed that the activity of the peripheral mechanism is probably not completely suppressed even in the presence of a normally acting circulatory apparatus; that it exerts a greater physiological influence in parts in which the circulation is normally some-what difficult; and that it unfolds an activity in pathological conditions in which the circulation has been eliminated or reduced in some parts of the body, or in which the energy of the entire circulation has been reduced.

"The results of attempts to cultivate trypanosomes from frogs." A preliminary report

During the year 1904 an effort was made in the pathological laboratory of the University of Buffalo to make studies on hematozoa in the lower animals. In a considerable number of normal cats, dogs, rabbits and guinea-pigs no hematozoa were found. The results of other examinations were as follows: 51 English sparrows {Passer domesticus), half in the winter, half in the spring, all negative; 27 mud-puppies (Necturus maculatus) in March, all negative; 40 toads in the summer, all negative. In 140 frogs from the Niagara river there occurred the following infections: 14 with Trypanosoma, 5 with Drepanidium, 1 with Filaria. Drepanidium was found both in the summer and fall. The infections with Trypanosoma were distributed as follows: In one case Trypanosoma and Drapanidium occurred in the same blood. The trypanosomes had the usual characters of Trypanosoma rotatarium (ranarum). They were in no case numerous; two were rarely seen in one low-power field. The frogs appeared healthy. Eight attempts to inoculate normal frogs by way of the peritoneum with the blood of infected frogs gave negative results. Attemps ad cultivation.— The blood of frogs and toads was taken to make blood-agar (used by Novy and MacNeal for the cultivation of trypanosomes). The blood was first examined carefully to see that it was free from parasites. The animal was etherized and placed in HgCl2 solution I to 1,000 for 15 minutes, rinsed with distilled water, opened with a11 precautions, the blood from the heart taken wit11 a sterile pipette, and mixed rapidly with the water of condensation on slanted agar tubes (made with meat extract and peptone, and slightly alkaline to litmus).

Scientific Serials

Studies from the Biological Laboratory of the Johns Hopkins University, Baltimore, vol. iv., Nos. 5 and 6.—No. 5 contains:—Some observations on the effect of light on the production of carbon dioxide gas by frogs, by H. Newell Martin and Julius Friedenwald. The influence exercised by light on the metabolisms of the animal body has been recognized for the last fifty years. Following up the researches of Moleschott, the authors experimentally proved that, in frogs deprived of their cerebral hemispheres, a greater quantity of carbon dioxide is given off in the light than in the dark; that, therefore, the influence of light in producing greater oxidations in normal frogs is simply reflex, and not due to greater bodily activity brought about by psychical conditions dependent on the light; that the cerebral hemispheres do not take any direct part in regulating the oxidations of the frog's body; and that this reflex action of the light, though mainly effected through the eyes, is produced partly also through the skin.—On the comparative physiological effects of certain members of the ethylic alcohol series (CH4O to C3H12O) on the isolated mammalian heart, by John C. Hemmeter. —On the ventricular epithelium of the frog's brain, by A. C. Wightman. The author concludes that the epithelial layer of the frog's brain and spinal cord forms a continuous lining to the central nervous system. It is everywhere a single layer thick. The epithelium of the ventricles forms a central zone of cells, about which the brain-cells are concentrically arranged. The cells of the epithelium and of the brain are connected by processes which extend from the tips of the former. The epithelial layer consists of cells of several varieties—the columnar, the spindle, and intermediate forms; all are ciliated.—On the temperature limits of the vitality of the mammalian heart, by H. Newell Martin and E. C. Applegarth.