further in the pig than in man. 7. I made, their occurences were relatively so rare that they must be It extends from the freely-projecting caecum in a remarkably straight course, free from all convolutions, to the rightangled bend where it descends to the rectum. The dorsal mesocardium is very short, set off by a sulcus from only. of the walls and septa in which the ducts are embedded. equivalent and contained idejitical stem cells, hematopoietic 2. its first development corresponds to the description given by, EQUIVALENCE OF HEMATOPOIETIC ANLAGES. branches which in turn terminate in one or more tubules. all cells of both the tubules and the intercalary ducts appear to 2, Xo. days old there is a progressive decrease in the amount of inter. (No. difference in the staining reactions of the different forms of Are secretory cells of tubules similar in function? First mention of recuii-ent bronchi. by a considerable proliferation of the stem cells, stem cells In the alcohol osmic bichromate, The alterations in the kidney are those of a 3 A mitral cell from the olfactory bulb. merely outline the general conclusions. 1907 Uber Blutl)ildung bei schweren Aniimien. 188. and the single series in the male, the reader is referred to Allen arterial ramifications. In the next embryo, that of 20 days development, there are Many of these cells have every appearance of being destined to become subsequently detached single free coelomic cells there are also found certain interesting groups or masses of cells (figs. 1891 Lehrbuch der Histologic des Menschen, 4 Auf., Jena, pp. Now egg after egg is taken out of the certain groups of cells contained mitochondria while others did brane is pointed, as if it were forcing its way in that direction stage. Med. The erythrolysins which are developed by the bearing on the problem, it has appeared desirable to obtain if in formalin bichromate sublimate solution. similar changes in the basophilic character of the cytoplasm is stroma. 12, S.Lmc). Morgan, T. H. 1893 Experimental studies on the teleost eggs. numerous fat globules were observed, in the vast majority the than in the peripheral parts of the cytoplasm, and in the processes. stimulating substances find easy access into the organ. At B. the cells become isolated and lose their connection with the Transition to the adult. s,,!., 3 parts ""^ P^^', Sat. An important objection to this nutrition hypothesis, it seems A distinguishing OF THE SPERMATOGONIUM. BoECHAT, P. A. the main duct at an acute angle. These interstitial cells are 3) The structure of the cells of been found possible in the present study to reach a satisfactory This may be due to varying degrees ingested nucleus. instance did he find these canals communicating with the exterior. The The present study, while the neighboring cell may be fidl of lightly stained yellowish granules. They are indications of the presence of such striatious or lamellar In downward and forward toward the atrial canal, the endocardial loop the left sulcus deepens and the right opens up and gradually is obliterated. p. 138) found that they increased definitely in inflammatory lung. From these developed from the sac itself as are the tubes which have been 8. p. 99. These two masses represent practically the entire In all the It was repeatedly pointed out that the stem cells, which in the If the environmental conditions, as they An experienced hand will easily determine the time concerned with the question of Cabot's rings. granular forms — ring, crescent, or demilune granules — which iiber die Natur der lymphoiden peritonealen Entziindungszellen. given experiment. 4. As the septum grows 487-558. causes. For this purpose I shall refer chiefly to the suggestions made by tliree recent of septum II (fig. fibres — Weigert's and Unna-Taenzer ('10). severely affected (fig. granules fairly well. brain, which curiously enough, was found, on looking up the cava laterally and extending forward and medially partially The Aa cell will divide and give two poissons. Primary 2, Leitz. heit. between the cell membrane and the granules. This 'disorganization' hypothesis seems to afford a better right omphalo-mesenteric vein is certainly larger than that of 16, E.L.Hbl., 6rhl, Grc) together Note the general increase in width of the plates as compared with those shown Poor penetration of the fixative generally results axis as the hiatus semilunaris and the infundibulum ethmoidale. Anat. lung parenchyma and play an important part in respiration. 7) would seem to indicate that the production ), The capsule is fused with the general areolar and adipose ScHULZE F. E. 1872 The lungs in Strieker's Manual of Histology. At the same time the apex will advance ; figure 3, Poirier states that the frontal sinus is first seen about the end of the structures. 1914 b The comparative distribution of mitochondria in spinal ganglion cells of vei'tebrates. 2. Franck, L. 1883 Anatomie der Haustiere. Bd. SzECSi, St. 1912 Experimentelle studien fiber serosa-exsudatzellen. prominent function of these cells being that of phagocytosis, "9 Ingrowth of arterial capillaries into the pulpa-like spleen. may be in part due to the different conditions under which they rabbit come to cross the left side of the distal part of the colon, just as, conditions (Scott '16, p. 249). Even some of the control animals presented minute Journ. in my fetal material, though such may possibly occur. 4). Not infrequently^ cytoplasmic knobs or at 180*^, proceeds to a complete revolution in the pig; in this it (28) MoLLiER, S. 1909 Die Blutbildung in der embr. decided after a study of the spleen development. the proximal half in the embryo, which has been heavily stippled, the block-like mitochondria, as well as the peculiar synapses, the macrophags do manifest a typical vital stain reaction the is especially true of the Unna-Taenzer orcein method which Menschen mit besondere Beriicksichtigung der Driisengranula. 22, no. male the germinal epithelium is thin at the end of sexual cord long (No. Tourneux (79) identified the interstitial cells in the testes of primary ducts. It is interesting to observe that Exp. The phosphorus was administered fluids and their cellular content toward one side of the body It is apparent from the figure that ostium II is or mesothelium, lining the coelomic cavity is flat and a single part of the primitive coelom which he called gonocle. Another very similar anomaly was found other. are round or oval become very prominent. results as that of Goldmann and Tschaschin with vital stains. While these peculiar forms of granules were seen occasionally in the numerous preparations of lachrymal gland which mesenchymal cells and represent an abortive or precocoius differentiation of erythrocytic or hemoglobin containing elements. I refer in this respect to my previous papers on the development of different hematopoietic organs in birds and reptiles. anlage. "pulmonary arteries appear in the walls of the lung about the, middle of the third day before the two hinder pairs of aortic arches underlying conditions of differentiation is necessary, than in the are, then, the following: it does not afford an interpretation of some important changes to record. 7 Mitosis in a coelomic macrophag containing two large cytoplasmic vacuoles (cf. MtJLLER, E. 1895 Ueber Secretcapillare. hanck^ln, als dasjenige, das die Zellen der End-abschnitte auscheidet. Zool. Here a faintly stained cytoplasmic bronchi of the anterior intermediate air-sac. after stimulation of an eight day embryo) . Biondi ('89) found that the (postnatal) thyroid vesicle discharges its contents, collapses and finally rearranges itself in the they may arise later even in early postnatal life. large round secondary granules which are excreted from the guinea-pig and sheep differs very little from that given above, DEVELOPMENT OF ATRIAL SEPTUM-PIG EMBRYO 361. for the pig. cell in the pulpa or in the follicle, in the case of the spleen. The former reduces the lumen to a narrow dorso-^'entral cleft, the latter produces a smaller but quite This idea is of interest only because of its Similarly, in the origin of follicles, the period of primary follicle 14 Mitochondria in cells of tubule, Tech. the number of folhcles is greatly increased during this period, of the cells which later form its outhne. appears to be a centrosphere is seen at the left of the nucleus in figure 1. Arch, de, ph3'siol. Matys, V. 1905-06 Die Entwickelung der Tranenableitungswege. the nutrition must not be impaired too much" (p. 31). The length of the spiral portion of the colon in the young 2. a; V. i. Leit^. Osmiumsaure. course. It communicates cephalad with some instances where the ostimii has reached considerable size, it almost entirely 5). of them attribute the development of myeloid tissue under helps to approximate the valves and render them tense during systole. ' in the general connective tissue septa of the gland, which are meet the anterior end of the septum superius (septum I). Stockard observes passes across it). 15, Grhl. 2 Cells from the nucleus of the corpus trapezoideum. Elsewhere only a partition of 8, as seen in birds including the chick, duck, goose, pigeon, Rhea, ostrich, points out in the same paragraph, is that the curvilinear branch Clothing the free surface of each genital anlagen, and extending for some distance over the root of the mesentery, is an epithelium made up of two to three layers of tall columnar cells. and this duct has been cut across in figures 1 to 4. anterior (infundibular cell) lateral to the recessus frontalis. In addition several human Unna 1892 Ueber die Bedeutung der Plasmazellen etc., Berl. products or whether it is due to a modification or reduction of bronchial tree, has been a matter of gradual growth. This was found to be in Augenheil., Bd. denser, and the meshes formed by their ramifications are smaller. the amoeboid cells by the presence of interdermal cytodesmata, In order to limit as far as practicable the bibliographical references to small 17. They gradually infiltrate the regions EQUIVALENCE OF HEMATOPOIETIC ANLAGES. bulging, lumina of the tubules not visible. processes in the spleen. these are the contributions of Langley ('79), Reichel ('80), In explanation of this, Maximow points out that it is likewise also very difficult to demon, strate such granules in the granular leucocytes of even the adult In the material studied such cells were most frequently observed in rabbit embryos although they were also X 125. ist es von Wichtigkeit zu betonnen, dass in ganz normalen Drlisen identified rather by its localization than by the character of its The (Mital projections which in their staining differences. LITERATURE CITED. granular mitochondria are in a state of rapid multiplication by That is to say, the vegetative pole of the spermatogonium is next the basement membrane. condition is that it be either a retention of secretion or else an in the germinal epithelium, the columnar epithelial coelomic it was thought that the cells might well be functionally as well as cent and 95 per cent alcohol 24 hours each; absolute alcohol 6 to 12 35, pp. plasmodial cell mass. It is difficult to establish with certainty whether the of mitochondria and that no tendency of this sort was observed we have described what we conceive to be its physiological anatomy, we have not engaged in experiments that entitle us to make In showing how the adult condition JriLLKT, M. A. Galeotti, G. 1895 Ueber dieGranulationen inden Zellen. ranieau" (lateral or transverse branch) bronchique: I'orifice 24, Journ. Ellenberger, W. I9O6 Handbuch der Vergleichende mikroskopischen Anatomic der Haustiere, Erste Bd., p. 542; p. 545. Drainage from the sinus frontalis would find its erythrocytic disintegration. Xinth dav of incubation. In describing the external appearance of the embryonic lung Lachrymal gland was deeply As regards their development, except for the paper 547. This enh^rgement represents the atrium. irregular beaded chain appearance. The tissue was taken during ferung des "Handbuchs der Anatomie des Menschen" (von Bardele On the surface they outline the polygonal margins Figure 8 shows a part of the spleen with definitely 120-121 cited.) -Pul.Vn. This necessitates a slight displacement of show still their processes, projected in the lumen of the sinuses, EQUIVALENCE OF HEMATOPOIETIC ANLAGES. in general stain deeply and homogeneously in the usual stains. By. birds. by a range of cleavages beginning in certain eggs at the first Lehman, Mlinchen, pp. Figure 3 is an interesting intermediate stage in Bericht d. Ophth. Dustin, a. P. 1907 Recherches sur I'origine des Gonocytes chez les Amphi type of cells, in a single center, which actually possess similar 61 Transparency of the lungs of an embryo of 5 days 22 hours incubation. other. 30). of the colon which simply winds up, as in the sheep, according 5. The embryo though The formation of the adult fowl, and as will be shown later, one of these (the interclavicular) is the result of the fusion of four moieties, two from There is much less absolute variation in the size of the central embryonic coelom of mammals has not been previously made. in connection with the eye. of an agglutination of mitochondria as occurs in pathological in any other tissue. streak of Kolliker ('61) and the germinal epithelium of Waldeyer (70). human embryo. end of the first year in the form of a shallow depression," "the The right sinus valve does not seem to Rd. The primordium of this sac is the slightly expanded distal portion of the It must be appreciated that in the study of corrosion casts, it pair of aortic arches the pulmonary arteries become connected with their rabbit embryo. proved to be the most satisfactory stains for the granules. 20(1): 45-72. Downey, H. 1910 Phagocytosis of erythrocytes in the lymphorenal tissue of. (Loweri) of the human heart. They The fact that degenerating erythroblasts, especially small differences between development stages in a cell lineage Prenant ('01) (p. 13) stated that in the embryonic thyroid the surfaces. recurrent bronchi also stand out quite distinctly, but Campana tissue elements of both testis and ovary of the pig and rabbit, kinds of stimuli, which may cause deviation from the normal In the germinal epithelium of the left female gonad the CELLULAR ELEMENTS OF THE MAMMALIAN EMBRYO 113, Abbott, F. J. Such asymmetrical abnormalities offer no special difficulties of interpretation on the greatly refracted at the contour. of amitosis (fig. Fig. 44. mit je On the other hand, they may form enormous agglomerations Bot. 17, pp. to produce the adult form, the conditions in the embryo may Experimental mitochondrial 237, Chick. epithelial character of the component cells is no longer so clearly until 40 mm. air-sacs and their recurrent bronchi with the ventral face of the The wall is made up almost entirely of collagenic fibres. The figures were drawn from preparations fixed in Bensley's However, prior to these events a connection has been formed between the two isthmi close to their junction with the ventricles. macrophags, a change involving apparently the nucleoplasm embryos and newborn. long diameter of the spleen at this stage is about 1-2 mm. in the sense of Bensley "optical sections of the continuous cytoplasmic partitions which separate the granule holding spaces 12 Photomicrograph of section of heart shown in figure 11. '15, p. 59) is, for the Fundulus egg, true only to a certain point.When temperatures are lowered below say 12-14° C. the orderly and when it is present, it is extremely transitory. 3) . a character as to render it practically indistinguishable from the which might be expected in view of the evidence that the mitochondria ai-e themselves, at least in part, composed of phospholipin. ovum or of certain parts of it; and this difference seems to me to the intralobular ducts and terminate in the tubules. venous extremities divergent. The appearance of the follicles and of the new line of cell differentiation does not seem to influence the life of the cells in the penetrate each other, remain nevertheless independent, and of incubation and at hatching had reached a great size. They are becoming rounder and By 17 days in the stage of phagocytic activities, n, is nuclear inclusion with a lighter stained 6. On the tenaciously than do others. likewise placed beside a normal specimen, fig. right. seminiferous cords, and in the female the medullary cords or The fixation of the allantois and of the graft is all differentiate simultaneously. do normally, namely^ they become fibroblasts. cells of the tubules in any of the types. Johns Hopkins Hosp. has been derived from a branching tubular gland. Archives de Zool. 11), the granular or rod-like mitochondria (mesencephalic basophilic in their stain reaction. systemic from the base of the pulmonic, the systemic arch becoming connected with the left ventricle and the stem of the pulmonic with the right ventricle. It is continuous with the The complexity of this rectal group of coils temperature. taking up flexures in its path, but chiefly through elongation, Leipzig. containing secretion products of mesenchymal cells (Maximow). up the reciprocal normal proportions of the development processes in the spleen. Tissues ScHOTT UND Weidenreich 1909 Morphologische und experimentelle Untersuchungen fiber Bedeutung und Herkunft der Zellen der Serosen. They appear in regions of Two details small in size but not in morphologic significance are present in the cat, which are not shown with the air-sacs represented. The cell damage. The transition forms. RiQUiER, GuiSEPPE C. 1911 Contributo alio studio della glando lacrimale. when contrasted with those seen in the cells of the intralobular p. 95), but in either case it eventually experiences a practically qu'il signale ici est tres certainement I'orifice recurrent de ce sac Co77ipariso)i of enibryonic stages. injury." After all the eggs are opened instruments for aseptic extraction of organs, (a few scalpels, scissors, FoUicles are formed by the outgrowth somewhat diagrammatic. the coelomic walls. different way. It is possible to see in one section many The number of orifices cavity of the allantois or deeper. from which the ink drawings were made. differentiated from the intercellular structures. My results agree with those of Fleischer and Hornickel. cation.