THE LIFE HISTORY OF POLYSIPHONIA VIOLACEA. 
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY. 
LXXXIII. 
SHIGEO YAMANOUCHI. 
Tuts preliminary paper will give a brief sketch of my cytological 
studies on Polysiphonia violacea Grev., which were begun last sum- 
mer at the Marine Biological Laboratory, Woods Hole, Mass., where 
I occupied a Carnegie Research Table, and were continued at the 
Hull Botanical Laboratory as a Fellow in the University of Chicago. 
The problem was suggested by Dr. BRADLEY M. Davis, to whom I 
wish to acknowledge my great indebtedness for his assistance and 
criticism during the progress of the investigation. 
Many points, which for the sake of brevity are omitted in this 
paper, together with a discussion of literature will be presented in a 
detailed account with plates to be published later. 
METHODS. 
The material was killed and fixed in Flemming’s fluids, in several 
modifications which contained the osmic acid in various proportion, 
Hermann’s fluid, I per cent. picric acid, and others; among which 
the weaker formulae of Flemming proved most effective. The best 
fixation for the study of spermatogenesis and the germination of car- 
Pospores and tetraspores was obtained in material killed in weak 
chrom-acetic acid (Flemming’s formula), without any osmic, as fol- 
lows: 1 per cent. chromic acid, 25°°; 1 per cent. glacial acetic acid, 
Io“; sea water, 65°. 
Material was left in the fixing fluid five to forty minutes, and 
then washed in a gentle stream of sea water. If material remains for 
a longer time in chrom-acetic acid it becomes very soft and breaks 
apart. The washed material was passed very gradually through a 
series of alcohols beginning with 30 per cent., and imbedded in 52° 
paraffin. The sections were cut 3-5 # in thickness and stained with 
safranin-gentian-violet or with iron-alum-haematoxylin, sometimes 
followed by some plasma stains as crange G, Bordeaux red, Congo 
425] [Botanical Gazette, vol. 41 
