On the Behaviour of the Nuclei during the Conjugation of Zygnema. 
a a RP ST EE, 



CO that in which it is formed, not within any of these cells, but within the common canal formed between 
r 
them. Klebahn’s observations refer exclusively to Zygnema belonging to the first class. It is the purpose 
of this paper to establish the fusion of two nuclei in one species belonging to the second class and to 
describe their somewhat peculiar behaviour during the process. 
= 
a Now firstly as to the mode of preparation. My observations have almost exclusively been executed on 
materials which were hardened, stained, and imbedded in Canada-balsam, because fresh materials give but an 
ーー 
ーー 
imperfect image. Algal filaments are hardened and stained in either of the two ways mentioned below: 
firstly, they are hardened and stained simultaneously by means of Pfitzer’s Picro-nigrosin™’, in which they lie 
at least for one night and are then washed with very dilute glycerin; secondly, they are hardened by 1 % 
chromic acid, washed during several hours with running water, stained with Delafield’s Haematoxylin, im 
which they lie at least for one night, washed with 2 % alum solution, and then washed repeatedly with 
distilled water. Algae hardened and stained in either of these two ways are then transferred to 20-50 % 
alcohol, which is then made to concentrate gradually almost to 100 % by diffusion method’, then again 
REorTLAHRSe E+ 
transferred to 10 % solution of turpentine in absolute alcohol ; Overton’s arraneement is then made to make 
/ 2 の 

() Pfitzer, Ueber ein Hirtung und Firbung vereinigendes Verfahren fiir die Untersuchung des plasmatischen Zellleibes, Ber. d. deuts. boi. 
Ges. Bd, I, 1883. 
(2) Strasburger, Botanisches Practicum, 2. Aufl., 1887, p. 515. 
(3) Overton, Mikrotechnische Mittheilungen ete. Zeits, f. wiss. Mikroskopie. Bd. VII. Heft 1. 
oR ee ee a ee 1 


