Microscopic Animals Research Articles

The Microbe—Friend and Enemy of Man

THE world in which we live is inhabited by a multitude of microscopic forms of life that we commonly refer to as microbes. They comprise the bacteria, the fungi or the molds, the protozoa and other microscopic animal forms, and the ultramicroscopic forms known as viruses. These microbes are devoid of chlorophyll, and are thus unable to utilize the energy of sunlight; they have to depend, therefore, for their nutrition, upon the preformed organic materials in the form ot living matter or dead plant and animal residues; only few of the microbes are able to synthesize their cell substance from simple inorganic elements and compounds. Microbes bear an intimate relation to the cycle of life in nature, and thus affect our health, our food supply, our shelter and clothing, and many of our industrial processes. Microbes vary greatly in their structure, in appearance, and mode of living. Some prefer one kind of food and ...

A New Nematode-Capturing Dactylella and Several Related Hyphomycetes

In two earlier papers (2, 3) descriptive accounts were given of twenty-one interrelated mucedinaceous fungi observed capturing and consuming actively motile eelworms in transparent agar plate cultures planted with softened discolored rootlets or, at times, with various other decaying materials. A twenty-second mucedinaceous fungus of similar predaceous character and having taxonomic kinship in the same intimate series is described herein as a new species. Occasion is taken to describe likewise as new species three hyphomycetous forms which together with a fourth form identified as Dactylaria pulchra Linder (7) apparently also belong in the series, though so far none of the four have been demonstrated either to capture microscopic animals or to subsist habitually as parasites.

AN APPARATUS FOR MEASURING THE "FLASH" THERMAL DEATH POINT OF MICROSCOPIC ANIMAL ORGANISMS AND ITS USE WITH OVA OF ASCARIS LUMBRICOIDES

A method of measuring "flash" thermal death points of microscopic animal organisms is described. By means of the devised apparatus the time of exposure can be varied from 0.5 to 0.1 second, and the temperature can be estimated with relative accuracy. In a sample determination, the single-celled ova of Ascaris lumbricoides (porcine origin) were all destroyed at a temperature of 68 °C. in an exposure of 0.44 second.

BIOLOGICAL OBSERVATIONS ON THE MARINE FUNGI OF WOODS HOLE WATERS

In the foregoing paper are described fifteen species of phycomycetous marine fungi, two myxomycetes, and a Protomyxa-like protozoan, all collected in the vicinity of Woods Hole, Mass. Included in these are two new genera and two new species. With one exception, the fungi were either parasites, facultative saprophytes, or saprophytes on various species of marine algae. One was found parasitizing the eggs of a microscopic animal, probably a rotifer. The results of preliminary attempts to culture Sirolpidium bryopsidis, a facultative saprophyte of the green alga, Bryopsis plumosa, are reported. None of these fungi, with perhaps the exception of Rhizophidium discinctum, has heretofore been known from the United States. The existence of true marine fungi, their work as one of the several types of reducers in the sea, and their possible importance in the formation of marine humus are discussed in particular.

Experimental Evidence of the Function of the Fibrillar System in Certain Protozoa

Ix a memoir published in 1838 onl organization in the Infusoria, Dujardin1 concluded about as follows: Organs of the Infusoria possess a degree of organization that is in keeping with tlleir manner of life and these organs are not comiparable with the organ systems of higher animals. This statement. was a refutation directed against claims advanced by Ehrenberg which in effect were that in these miniature animals, the Infusoria, it was possible to identify complex organs and organ systems that perfornied all the principal functions of animal life. Have Infusoria vision ? According to Eli renberg the conspicuous red eye-spot of Euglena represented a higlhlv differentiated visual organ. As regards a digestive system, he described and illustrated for EKnchtelis, Leucophri'ys and other ciliates a permanent and complete alimentary tract having a mouth and anal pore. Other organ syTstellms were also in evidence: an elaborate reproductive system provided with a testis (a structure we now call the nucleus), a seminal vesicle (the contractile vacuole), and numerous eggs (the granules distributed throughout the body). In addition, Ehrenberg urged, although he did not identify, for these microscopic animals a complex nervous, muscular and circulatory systellm. These premature interpretations were early called in question and were successfully refuted during Ills owln lifetime. His first and probably foremost critic was Dujardin, who is nowT relmlenibereid rather as the discoverer of the living substance composing these lower forims. This historic discovery of sarcode, it is interest-

The Arthropod Enemies of Mollusks, with Description of a New Dipterous Parasite from Brazil

The Mollusca are, next to the Arthropoda, the largest phylum of the Animal Kingdom. They exist in innumerable species in the sea, in fresh waters, and on land, where they frequently occur in populous colonies. It might therefore seem that their soft and succulent bodies would be an important item in the diet of the many carnivorous arthropods. Yet such is not the case. In the light of our present knowledge rapacious snails appear to be the most formidable predaceous enemies of mollusks. Against predatory arthropods, snails and bivalves are generally well protected by a calcareous shell, the aperture of which is frequently obstructed by folds or teeth, or in some species may be completely closed with an operculum. In the case of the bare-bodied slugs, the violent contractions of the body and the abundant slimy secretion of the skin seemingly are quite effective repellents. Moreover, the secretive habits of snails and slugs contribute much to their personal safety. Many species are strictly nocturnal or crawl about during rainstorms only, that is when most of their potential enemies are inactive. At other times they are safely hidden in inaccessible recesses or buried in the soil, often at great depth. Among lower arthropods several species of mites (Acarina) infest land mollusks. Thus Erynetes limaceum Koch is commonly found in Europe on the slug Limax maxinmus Linnaeus and some of the Helicidae, retiring upon occasion into the pulmonary chamber (Cooke, 1895:62). In North America a mite (Hypopus concolor Haldeman) has been recorded by Binney as found upon a snail; it may have been a nymphal form of Erynetes. I have observed minute, ectoparasitic mites on a living Achatina in the Semliki forest of the Belgian Congo. Stuhlmann (1894: 313) had found them before in the same region with Achatina schweinfurthi v. Martens and A. stuhlmanni v. Martens. The acarids that parasitize fresh-water mollusks are much better known. They are aquatic mites (Hydrachnidae) of the genus Unionicola Haldeman (= Atax Fabricius) and are most frequently found in the naiads or Unionidae, where they often are fixed on the gills. They are said to feed on the microscopic animals drawn in by the mussel. Kiichenmeister (1856) has shown that they may become the center of a pearl growth, although this more commonly is formed around an

The Abundance and Migration of Turtles

During the past few years there has been renewed interest in aquatic resources, and a number of attempts have been made to evaluate various aquatic habitats. Johnstone (i9ii) and others have summarized the older work in this field; Petersen (i9i8) made an exhaustive study of the sea bottom; and, in the United States, Kofoid (1903, i908), Baker (i9i8), and Richardson (1921) have recently investigated fresh-water habitats. Much has been learned concerning aquatic animals: their numbers in unit areas; their seasonal and ecological succession; the rapidity of their overturn; their chemical composition and economic value. It is comparatively easy to count microscopic plankton animals or the sluggish inhabitants of the bottom, but it is much more difficult to determine the number of large, freely moving animals in a particular area. The present paper deals with observations on turtles: the population of a shallow bay, the distribution and migration of the inhabitants of such an area. The region investigated was the shallow water behind a bar in University Bay, which is a part of Lake Mendota, Wisconsin (fig. i). The area was about 900 meters long, 225 meters wide, and included about 202.5 hectares (546.75 acres). The writer was led to take tup the tagging of turtles more or less by accident-through attempts to study the growth and migrations of fishes by marking them with aluminum tags. During the year 1917, 1,643 fishes and 15 turtles were marked with band tags. Only two fishes were recovered. One was a pumpkinseed which was caught by a fisherman where it had been released two weeks later. Nine hundred and sixty-six of the fishes released in 1917 were yellow perch that were put into deep water (15 meters). Although fishing with gill nets was continued at intervals throughout the summer for a total of 33 days at three stations, only one of these perch was recaught, indicating that the number of perch in the deeper parts of Lake Mendota must be enormous. In i919 a new style of button tag was used; i,6oo fishes and 12 turtles were marked and all were released at certain stations in shallow water. Efforts were made to recover the fishes by seining at intervals at the stations where they had been released, but the results were of little value. No fishes were caught except at stations where they had been released, and the recapture of fishes therefore only furnished evidence as to how long a particular fish had remained in a certain locality. The longest periods before recapture for

THE STRUCTURE, LIFE HISTORY, AND INTRAGENERIC RELATIONSHIPS OF PARAMECIUM CALKINSI, SP. NOV

The term Paramecium was coined by Dr. John Hill of London in 1752 for a group of animalcules comprising “? four species,― two of which probably inc,lude members of the genus Paramecium as recognized today.' Then 0. F. MUller in 17732 named an organism Parama@cium aurelia, and in 1786,' in the first compre hensive attempt to classify scientifically microscopic animals, definitely established the genus Paramecium and included under it five species. Unfortunately, however, without the slightest warrant etymological or otherwise, Muller changed the spelling of Paramecium to Parama@cium. Among the species which MUller distinguished are Paramcecium aurelia and Parama@cium versutum. The former apparently is Hill's “? species 3―and either the present-day P. aurelia or P. caudatum. Paramcecium ver sutum possibly is Hill's “? species I―and apparently the present species P. bursaria. Muller's othet paramecia have stnce been relegated to other genera. Ehrenberg, in his great monograph on the Infusoria4 (1838), recognized eight species under the genus and returned to the spelling of Hill with the note “? Paramecium ist richtiger als Parama@cium.― Among Ehrenberg's species are two true paramecia: Paramecium aurelia, which he assumed to be the P. aurelia of Muller, and P. caudatum, which he distinguished from P. aurelia chiefly by the greater attenuation of the posterior end of the animal. Muller's species P. versutum, to which Focke in the meantime5 had given the name Paramecium bursaria, Ehrenberg placed under the genus Loxodes as L. bursaria.

ALLERGY

A person who has once had measles, smallpox or whooping-cough does not, as a rule, have the infection a second time. We call this immunity. On the other hand, there are infectious diseases, such as pneumonia and erysipelas, which leave behind a greater sensibility, which we call predisposition. For half a century the medical world has worked on the mechanism of these phenomena. The great discoveries made in this field have been the result of our knowledge of the pathogenic micro-organism, together with that of the morphological elements and the soluble constituents of the blood and other organs. It is not surprising that the greatest attention has been paid to microscopic observations and animal experimentation, while the study of the clinical phenomena has been comparatively neglected. <h3>THE CLINICAL OBSERVATION OF THE MECHANISM OF IMMUNITY</h3> The question we put ourselves is: what occurs if we try to reinfect an

Microscopic Marine Organisms in the Service of Hydrography

It has for a long time been known that the sea abounds in microscopic organisms, both animal and vegetable. Among the former are entomostraca, infusoria, radiolarians, foraminifera, as well as larvae of mollusca, radiates, and bryozoa. Among the plant-life the mass consists of diatoms, cilioflagellates, flagellates, and certain unicellular chlorophyllaceous algae. For these pelagic forms Prof. Hensen has proposed the name plankton, which has been universally accepted.

Microscopic Marine Organisms in the Service of Hydrography

IT has for a long time been known that the sea abounds in microscopic organisms, both animal and vegetable. Among the former are entomostraca, infusoria, radiolarians, foraminifera, as well as larvæ of mollusca, radiates, and bryozoa. Among the plant-life the mass consists of diatoms, cilio-flagellates, flagellates, and certain unicellular chlorophyllaceous algæ. For these pelagic forms Prof. Hensen has proposed the name plankton, which has been universally accepted.

New species of microscopic animals

JOURNAL ARTICLE| 01 October 1867 Original Communications: New Species of Microscopic Animals T. G. TATEM T. G. TATEM Search for other works by this author on: This site PubMed Google Scholar Author and article information T. G. TATEM Online Issn: 1477-9137 Print Issn: 0021-9533 Copyright © 1867 by the Company of Biologists Ltd.1867 J Cell Sci (1867) s2-7 (28): 251–253. https://doi.org/10.1242/jcs.s2-7.28.251 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation T. G. TATEM; Original Communications: New Species of Microscopic Animals. J Cell Sci 1 October 1867; s2-7 (28): 251–253. doi: https://doi.org/10.1242/jcs.s2-7.28.251 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All contentAll journalsJournal of Cell Science Search Advanced Search This content is only available via PDF. Copyright © 1867 by the Company of Biologists Ltd.1867 Article PDF first page preview Close Modal You do not currently have access to this content.

On the Remains of Microscopic Animals in the Rocks of Yorkshire

There is nothing more certainly proved, more generally known, or more important in Geological reasoning, than the fact that a very considerable portion of the stratified masses of the globe is composed of the remains of organized beings. Changed vegetables have yielded our coal—changed Zoophyta compose the entire mass of some limestones—shells contribute to augment the thickness of almost all the strata which rest upon the Gneiss and Mica schist groups. It is also known, that, in very many instances, plants and Zoophyta occur in a fossil state, on the very spots where they were attached in life; that they did actually grow and perish where now we find their remains. Shells in like manner appear with all the marks of being entombed on or near to the very localities where their molluscous tenants respired and fed; the valves of oysters are yet attached to the rock, stone, or old shell on which the young ova fixed themselves; lithodomous Conchifers yet occupy the very holes which they have bored; Cardiacea and Veneridae yet display their valves, as closed by the muscles in life, or partially opened by the decay of these muscles, or separated by the decay of the ligament, or finally broken and worn by the agitation of the water in which they died. It follows, from investigations of this kind, that in the same physical area of the earth’s surface, but at successive times, different races of plants and animals lived, whose specific forms changed with ...