Volume 1

Elements of physiology : for the use of students, and with especial reference to the wants of practitioners / Tr. from the German, with additions by Robert Willis.

  • Rudolf Wagner
Date:
1841-2
Catalogue details

Licence: Public Domain Mark

Credit: Elements of physiology : for the use of students, and with especial reference to the wants of practitioners / Tr. from the German, with additions by Robert Willis. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

    224/244 page 214
    311 Origin and Evolution of the Tissues. § 86. The present state of our knowledge of the histogenesis, or doctrine of the fonnation of the tissues, renders it probable, that all the tissues result from metamorphoses of the primordial cells of the germinal membrane and vitellus. The first indications of histological difference appear in the three latninee of the germinal membrane, which then immediately afford the elements of all the succeeding tissues. The structure of these tissues wiU faU under consideration by and by, in the particular appropriate sections of the different books of this work; in the following annotations, the history of the development of the several tissues will be found sketched in general and broad outhnes. Professor Valentin at my request has furnished me with a gene- ral survey of the subject of histogeny, which I communicate here entire, and as it came into my hands. PRINCIPAL FEATURES IN THE DEVELOPMENT OF THE ANIMAL TISSUES, BY G. VALENTIN. In my first histogerxetic inquiries, I observed certain peculiar granules embedded in transparent gelatine, as the elementary matter of all the tissues. I remai-ked the diflFerence between these granules in the serous and mucous laminae, at the period of the earliest separation of these layers from one another. In the vascular lamina I found large globules or cells, which in form and mode of mutual appo- sition I likened, so long ago as the year 1835, to the cellular tissue of vegetables {Entwickelungsgeschichte, 287). I filso first directed attention to the resemblance in form and appearance of the cartilages beginning to be ossified, particularly of the branchial cartilage in the larva of the frog (from observations made in con- junction with Purkinje), to the cellular tissue of plants (ib. 209, 210). I de- scribed the round cells of the globules with their interposed cellular substance, of the cliorda dorsalis of young embryos {ih. 157, and Reptrtor. i. ]87). Shortly after this, I. Mliller, from his own independent observations, announced the cellular structure of the chorda dorsalis of fishes (on the Myxinoids, 74). In the Epithelium, which Purkinje and Raschkow (Melet. c, mammal, dent, evolut. 12), as well as myself {Nov. Act. Ac. N. C. vol. xviii. p. i. 96), compared to the cellu- lar tissue of plants, I chose, expressly on account of this resemblance in form, the same designation for the central mass, viz. nucleus, just as I subsequently described the nucleolus which was observed by me at a later period (Repertor. i. 143). In the study of the Epithelium continued particularly by Henle and me, the analogy to the cellular tissue of vegetables could not be missed, and the independence of the cellular parietes was distinctly indicated {ib. i. 284). I had also seen that the nuclei were the j)arts first formed in the ])igment of the choroid coat of the eye {Eniwick. 194), and I comi)ared the pigmentary cells to the vegetable cellular
    digitised image 1
    digitised image 2
    digitised image 3