April 1892.] THE BOTANICAL SOCIETY OF EDIXBURGH. 351 



The Embryo-sac of Myosurus minlmus, L. : A Cell Study. i 

 By GusTAV Mann. 



(With Plates Ilia and IV.) 

 (Read at the Meeting of the Society on January 28, 1892.) 



In a previous paper* a short account was given of some 

 facts which seemed to me to disprove the view generally held 

 that the embryo-sac of Angiosperms is a macrospore. As 

 several treatises on the same subject have since then come 

 to ray hand, and as I have made out some further interesting 

 points in the structure of nuclei and nucleoli, a detailed 

 account of my researches, accompanied by illustrations, may, 

 I hope, prove to be of service to all who consider the study 

 of cells the surest way of gaining an insight into the great 

 problem of Life. 



The methods employed in my investigation were shortly 

 these : Flowers in all stages of development were fixed and 

 hardened in my picro-corrosive-alcohol,t this fluid being 

 very gradually replaced by pure absolute alcohol, by chloro- 

 form and ultimately by paraffin. Great care was taken to 

 raise the flowers gradually to the temperature of melted 

 paraffin (50° C), and not to leave them longer at this 

 temperature than was absolutely necessary for perfect 

 imbedding. Finally the paraffin was allowed to cool 

 gradually. 



For sectioning I have used the Cambridge rocking- 

 microtome, the feed consisting for ordinary work of two 

 teeth (thickness of sections equal to 1'27 ^ or -g-jy^^ij^j of an 

 inch), but whenever a doubtful point arose the feed was 

 made to consist of only one tooth (thickness of section equal 

 to '635 fi, or 4^,77(311 °^ ^^^ inch). The sections were fixed 

 serially by means of Schallibaum's fixative on ordinary 

 microscopic slides, or for special investigation on No. 1 cover- 

 glasses (lA x 3 inches). The mounting on thin cover-glasses 

 has the advantage of allowing one to study the sections from 

 two sides. 



As staining reagents I have used with preference 



Kleinenberg's hsematoxylin No. 1 with 20 p.c. of absolute 



* Trans. Bot. See. Edin., vol. xix. (June 1891) p. 136. See also Trans. 

 Bot: Soc, xix. pp. 67 and 89. 

 t Trans. Bot. Soc, vol. xviii. p. 432. 



^ Received for publication April 1892. Issued July 1892. 



