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    Studies in Spermatogenesis Part I
    Studies in Spermatogenesis Part I
    Studies in Spermatogenesis Part I
    Ebook87 pages43 minutes

    Studies in Spermatogenesis Part I

    By Nettie Maria Stevens

    ()

    Read preview
    LanguageEnglish
    PublisherArchive Classics
    Release dateNov 27, 2013
    Studies in Spermatogenesis Part I

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      Book preview

      Studies in Spermatogenesis Part I - Nettie Maria Stevens

      The Project Gutenberg EBook of Studies in Spermatogenesis (Part 1 of 2), by

      Nettie Maria Stevens

      This eBook is for the use of anyone anywhere at no cost and with

      almost no restrictions whatsoever. You may copy it, give it away or

      re-use it under the terms of the Project Gutenberg License included

      with this eBook or online at www.gutenberg.net

      Title: Studies in Spermatogenesis (Part 1 of 2)

      Author: Nettie Maria Stevens

      Release Date: March 7, 2010 [EBook #31545]

      Language: English

      *** START OF THIS PROJECT GUTENBERG EBOOK STUDIES IN SPERMATOGENESIS (1 OF 2) ***

      Produced by Bryan Ness, Josephine Paolucci and the Online

      Distributed Proofreading Team at http://www.pgdp.net. (This

      file was produced from images generously made available

      by The Internet Archive/American Libraries.)

      STUDIES IN SPERMATOGENESIS

      WITH ESPECIAL REFERENCE TO THE

      ACCESSORY CHROMOSOME

      BY N. M. STEVENS.

      WASHINGTON, D. C.:

      Published by the Carnegie Institution of Washington

      September, 1905.

      CARNEGIE INSTITUTION OF WASHINGTON

      PUBLICATION No. 36

      FROM THE PRESS OF

      THE HENRY E. WILKENS PRINTING CO.

      WASHINGTON, D. C.

      STUDIES IN SPERMATOGENESIS WITH ESPECIAL REFERENCE TO THE ACCESSORY CHROMOSOME.

      By N. M. Stevens.

      In connection with the problem of sex determination it has seemed necessary to investigate further the so-called accessory chromosome, which, according to McClung ('02), may be a sex determinant. This view has been supported by Sutton ('02) in his work on Brachystola magna, but rejected by Miss Wallace ('05) for the spider.

      The forms selected for study have been taken from several groups of insects, and are all species whose spermatogenesis has not been previously worked out. They are (1) a California termite, Termopsis angusticollis; (2) a California sand-cricket, Stenopelmatus; (3) the croton-bug, Blattella germanica; (4) the common meal-worm, Tenebrio molitor; and (5) one of the aphids, Aphis œnotheræ.

      A brief account of a chromatin element resembling the accessory chromosome in Sagitta has been added for comparison. The spermatogenesis of each form will be described in detail, and a general discussion of the results and their relation to the accessory chromosome and sex determination will follow. The spermatogenesis of the aphid has been included in another paper, but a summary of results and a few figures will be given here for reference in the general discussion.

      METHODS.

      The testes were fixed in various fluids—Flemming's strong solution, Hermann's platino-aceto-osmic, Gilson's mercuro-nitric, Lenhossek's alcoholic sublimate acetic, and corrosive acetic. Flemming's and Hermann's fluids followed by safranin gave good results in most cases. The mercuro-nitric solution and Lenhossek's fluid gave excellent fixation and were preferable to the osmic mixtures when it was desirable to stain the same material with iron-hæmatoxylin, and also with various anilin stains.

      Heidenhain's iron-hæmatoxylin, either alone or with orange G or erythrosin, was used more than any other one stain. With osmic fixation safranin gave better results in some cases, because of the abundance of spindle fibers and sphere substance which were stained by hæmatoxylin. The safranin-gentian combination used by Miss Wallace and others in the study of the accessory chromosome did not prove to be especially helpful with these forms. Thionin was found to be a very useful stain for distinguishing between the accessory chromosome and an ordinary nucleolus. Licht-grün was often used in combination with safranin.

      RESULTS OF INVESTIGATIONS.

      Termopsis angusticollis.

      In the termite it was not found to be practicable to dissect out the testes. The tip of the abdomen was therefore fixed and sectioned, young males whose wings were just apparent being used. The cells are all small, and could not be studied to advantage with less than 1500 magnification (Zeiss oil immersion 2

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