LIFE-HISTORY OF BUCEPHALUS HAIMEANUS. 637 
Flemming’s chromo-aceto-osmic mixture (weaker formula). 
Tissues were allowed to remain in this reagent for twenty- 
four hours and were then removed and washed in running 
water for twenty-four hours. 
In my study of Gasterostomum I have tried but three fixing 
agents: acetic sublimate solution, Gilson’s mixture, and cold 
saturated aqueous solution of corrosive sublimate warmed to 
35° C. The material preserved by the use of the last-named 
reagent has been satisfactory. 
For staining I have used borax carmine and acid borax 
carmine, both of which gave fairly good results; Delafield’s 
hematoxylin and eosin, which were useful; gentian violet, 
which was unsatisfactory ; Flemming’s triple stain (safranin, 
gentian violet and orange G.), which was excellent in the study 
of the germ-cells, and Heidenhain’s iron hematoxylin, with 
eosin as a counter stain. By far the best results were 
obtained by the use of this method. 
The material was imbedded in paraffin and cut in one, two, 
and three micron sections. | 
In studying the nervous system I used methylene blue as 
an intra-vitam stain, by means of which I was able to make 
out the topography of the nervous system as well as the 
scattered ganglion cells. 
For the study of the nervous system in preserved material 
I found Heidenhain’s iron hematoxylin with a counter stain 
of eosin in 95 per cent.alcohol most useful. Several chloride 
of gold methods were tried, none of which proved satis- 
factory. 
HisroricaAL Account oF GASTRROSTOMUM. 
Von Siebold (1, 1848) discovered and named Gastero- 
stomum fimbriatum, which he found in the intestine of 
Perca and Lucioperca. 
Wagener (2, 1852) described this species, giving also 
descriptions and figures of two new species, G. minimum, 
from Trigla microlepidota, and G. gracilescens = 
