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  • Life and Medical Sciences  (41)
  • 1925-1929  (41)
  • 1929  (41)
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  • 1925-1929  (41)
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  • 1
    Electronic Resource
    Electronic Resource
    On the development of imaginal buds in normal and mutant Drosophila melanogaster (1929)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 47 (1929), S. 135-199 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Definite information concerning the time of development and location of the different imaginal discs of Drosophila melanogaster was needed in order to interpret especially the gynandromorphs, mosaics, and intersexes that have been extensively reported in cultures of this fly. This information was also desirable for many of the mutant types. It was not known, for example, when an organ was reduced or absent, whether its imaginal disc showed a corresponding reduction, or whether it was full size in the larvae and pupae, and failed to carry through to the later stages.Three mutant types with eyes smaller than those of the wild type, namely, lozenge, bar, and eyeless, were examined. It was found that there is a corresponding difference in size as far back as the imaginal disc could be detected. Similarly for the two mutants, vestigial and no-wing. Conversely for the mutant, bithorax, in which the metathorax is larger than the normal and has assumed many of the characters of the normal mesothorax, the imaginal disc was correspondingly enlarged.It follows that the effects of the mutant genes for these characters can be observed in the very earliest condition of the imaginal disc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050470105
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  • 2
    Electronic Resource
    Electronic Resource
    The somatic chromosomes of the opossum (Didelphis virginiana) (1929)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 47 (1929), S. 201-225 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: There are eleven pairs of chromosomes in the somatic cells of the opossum.The sex chromosomes are of the x-x type in the female and the x-y type in the male.The number and type of the chromosomes are constant in the wide variety of tissues and organs studied, except that one dividing giant cell of the spleen showed an 8n number of chromosomes.The arrangement of the chromosomes in equatorial plates is that of an autosomal ring surrounding the centrally located sex chromosomes.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050470106
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  • 3
    Electronic Resource
    Electronic Resource
    The influence of thyroid deficiency on the structure and epinephrin content of the adrenal gland of the albino rat (Mus norvegicus albinus) (1929)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 48 (1929), S. 45-79 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: It was found that thyroid deficiency in the albino rat (Mus norvegicus albinus) is followed by a trend to increased concentration of epinephrin in the suprarenals. The basis of this lies in the relatively greater retrogression of the cortex as contrasted with the medulla which becomes a relatively greater proportion of the organ as a whole. Confirmatory evidence is found in cell counts per unit area and the part of the disappearance of lipoid from the cortical cells of the suprarenals of thyroidless animals.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050480103
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  • 4
    Electronic Resource
    Electronic Resource
    Growth and maturation in the parthenogenetic and sexual eggs of Moina macrocopa (1929)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 48 (1929), S. 123-151 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: From a study of over 1000 mothers, the female chromosome number appears to be 2N = 22; N = 11. The male number has not been exactly determined, but is presumably not haploid. Only one maturation division occurs in the parthenogenetic egg, and the authors have seen only one in the sexual egg. During the growth stages of the eggs, the chromatin is totally obscured by a large amount of deeply staining nucleolar material which exhibits several phases. Ultimately, this material is apparently absorbed into the ooplasm. Just before the egg is laid, the ovoid chromosomes, in late prophase or in metaphase, are seen in a germinal vesicle situated always at one side of the egg. The maturation division occurs immediately after egg laying. A degenerate body, hitherto undescribed, is noted in the ripe parthenogenetic egg, situated at the pole opposite the germinal vesicle. It is believed to arise by reorganization of nucleolar substance. The body in the sexual egg desribed by Weismann and Ishikawa ('91) as the Paracopulationzelle is noted and its interpretation by these authors questioned, but, for lack of sufficient evidence, no counter-explanation is offered. The possible relation between experimental sex control and the time of maturation division in the parathenogenetic egg is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050480106
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  • 5
    Electronic Resource
    Electronic Resource
    Studies in the origin of yolk. IV. Ogenesis of Periplaneta americana (1929)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 48 (1929), S. 253-279 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Technique. This work is based not only on the fixed preparations, but also on fresh cover-slip preparations treated with neutral red or 2 per cent osmic acid for a short time.Golgi elements and fatty yolk. The Golgi elements are hollow vesicular bodies with a distinct osmiophilic rim and a central osmiophobic substance. In the youngest oocyte they form a circumnuclear ring. Gradually the vesicles spread out, grow in size, store up fat in their interior, and give rise to the fatty yolk. On account of their higher refractive index, due to the presence of fat, the Golgi vesicles can be occasionally seen even in the young oocytes without any treatment.Mitochondria. The mitochondrial granules also form a circumnuclear ring and are later distributed uniformly.Albuminous yolk. The albuminous yolk is nucleolar in origin. Early in oogenesis, the nucleous buds off small, homogeneous, and highly chromatic particles in the cytoplasm, which sooner or later disappear. Subsequently, the nucleolus becomes less chromatic and develops vacuolar bodies in its interior, which, becoming vacuolated exactly like the parent nucleolus, migrate into the the cytoplasm. These bodies become more and more chromatic and travel toward the periphery of the egg, where they grow in size. Ultimately they break down into small, homogeneous, and highly chromatic bodies which are the definitive albuminous yolk spheres and which subsequently grow enormously in size.
    Additional Material: 25 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050480109
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  • 6
    Electronic Resource
    Electronic Resource
    Maturation of the male germ cells in the ratAided by grants from the Committee for Research in Problems of Sex of the National Research Council, administered by Prof. Herbert M. Evans, to whom the author is greatly indebted. (1929)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 48 (1929), S. 433-443 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Maturation of the male germ cells in the rat shows some slight modifications of the typical procedure in sex cells, a distinct and rather prolonged synapsis occurring before synizesis and a confused stage immediately after it. The clumping in synizesis is not extreme. In the mixed strain of rats both twenty-one and thirty-one tetrads appear in the late diakinesis. This procedure in the male resembles the maturation of the oocytes in only two points, the beginning of the process, the deutobroch nuclei, and the end of it when the haploid number of chromosomes take their places on the spindle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050480206
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  • 7
    Electronic Resource
    Electronic Resource
    Some phases in the embryonic development of Diacrisia virginica fabr. (Lepidoptera) (1929)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 48 (1929), S. 493-541 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cells of the blastoderm which are to form the serosa are two- to four-nucleate; the smaller cells of the embryonic rudiment, uninucleate. The band-like embryonic rudiment encircles the yolk at the equator of the egg. The amnion does not begin to form until after the serosa completely covers embryo and yolk. The epithelium of the midgut arises from cells situated at the tips of stomodaeum and proctodaeum. These cells, though not differentiated from adjacent ectoderm at the time of the invagination, are nevertheless interpreted as part of the preprimordium of the endoderm. In the eighty-four-hour stage a fold of amnion grows over the dorsal side of the embryo, entirely covering it in the course of the next few hours. A portion of the amnion thus forms the dorsal wall of the embryo. At the completion of the amnion the embryo rotates so that its ventral side is directed toward the egg center. The amnion raptures just before the larva begins to feed on the yolk which still remains around it. The serosa is consumed before hatching, which takes place about five and one-half days after deposition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050480209
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  • 8
    Electronic Resource
    Electronic Resource
    A histological study of the colic caeca in the bantam fowl (1929)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 48 (1929), S. 585-609 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The caeca of fourteen bantam fowls have been studied. These fowls ranged in age from six days' incubation to three years after hatching. Between the fifth and sixth days of incubation rectal caeca arise as evaginations from the intestine at the junction of the ileum with the colon. The develoing caeca closely resemble histologically the intestine to which they are attached.The caeca are essentially devoid of content until about the nineteenth day of incubation, but during the remaining days of incubation are gorged with a bluish-gray material similar to that found in the colon. Thus, an early defecatory function is indicated.In general, the proximal third of the caeca remains histologically similar to the intestine, but the distal two-thirds undergoes regression. The latter involves the atrophy of the epithelium and glands, accompanied by the appearance of lymphoid tissue. Much of the lymphoid tissue eventually disappears, to a large extent by atrophy and dissolution of the leukocytes. However, to some extent, lymphocytes develop into granulocytes which escape with other leukocytes into the lumina of the caeca and there disintegrate.Lymph nodules begin to appear in the caeca about one week after the chick hatches. The leukocytes, at least in part, arise in situ from the reticular stroma. Eosinophils arise in certain areas of the tunica propria, and in the earlier stages of their development resemble large lymphocytes, in the cytoplasm of which basophilic, amphophilic, and acidophilic granules are intermingled.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050480212
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  • 9
    Electronic Resource
    Electronic Resource
    The parietal fossa and related structures in the plagiostome fishes (1929)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 48 (1929), S. 543-561 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The parietal fossa or pit is situated in the middorsal line between the ear capsules. From its floor four (sometimes only two) apertures lead into the ear capsules. The anterior apertures are the foramina of the endolymphatic ducts; the posterior ones are the fenestrae. Through the fossa each endolymphatic duct passes from its formen to its external aperture in the dorsal integument, describing in its course a loop with the convexity directed anteriorly. The part of the duct involving the loop is enlarged into an endolymphatic pouch. Into the angle of this loop a small muscle is inserted which is a continuation of the anterior trunk muscles, or one taking a more lateral origin from the edge of the fossa. The fenestra may or may not be closed by a definite fenestral membrane. The posterior semicircular canal (posterior utriculus) bears a peculiar relation to the fenestra. The endolymphatic pouch, like the sacculus, contains otoconia, and sometimes siliceous sand grains. Various functions have been assigned to the endolymphatic organ. There is no convincing experimental evidence as to its significance.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050480210
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  • 10
    Electronic Resource
    Electronic Resource
    Binary fission in the amoeboid and flagellate phases of tetramitus rostratus (Protozoa) (1929)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 47 (1929), S. 37-87 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The vesicular nucleus of this amoeboflagellate is similar in structure in both phases of its life-cycle. It has a fairly large caryosome surrounded by a pericaryosomal area in which there are small oxyphilic pericaryosomal granules on a fine reticulum. On the inner surface of the definite caryotheca is a layer of epithecal chromatic granules.Nuclear division is similar in both amoeba and flagellate phases. During the prophase the nucleus enlarges, and the expanded caryosome becomes resolved into basophilic and oxyphilic components and assumes either an oblong, dumb-bell, or spindle shape. The pericaryosomal granules enlarge, shift about, and eventually become arranged in an equatorial band around the elongated caryosome. In the metaphase the equatorial plate of chromosomes appears after the inward migration of the pericaryosomal granules, accompanied by the formation of a definite intranuclear spindle, usually with polar masses, polar granules, and a centrodesmose. After the poleward migration of the daughter plates of chromosomes in the anaphase, the telophase constriction of the nuclear membrane produces two daughter nuclei with a portion of the spindle remaining outside. The epithecal layer of granules remains in place on the nuclear membrane during the entire process of mitosis. Plasmotomy normally follows mitosis, but may be delayed, giving rise to multinucleate individuals. In the flagellate the blepharoplast usually divides simultaneously with, but independently of, the nucleus. There are many divergences in the details of mitosis, but these are thought to be variations of one type of division rather than examples of different processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050470103
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