STUDIES IN THE EXPERIMENTAL ANAIA’SIS OF SEX. 207 
Studies in the Experimental Analysis of Sex. 
Part 10. — The Effect of Sacculina on the Storage of Fat and 
Glycogen, and on the Formation of Pigment by its Host. 
By 
Oeoftroy Smith, 
Fellow of New College, Oxford. 
It has been shown in previous studies that Sacculina 
elaborates fatty material in its roots at the expense of its 
host, and it has been stated that the livers of infected crabs 
show a more constantly abundaut suppl)^ of fat in the liver 
than normal crabs. Since the maturing ovary of the normal 
female crab also stores a fatty material in the form of yolk, 
and since at this time also the female shows an abundant 
supply of fat in the liver, and, moreover, exhibits charac- 
teristic changes in the blood, which becomes loaded with 
yellow lipochrome (lutein) and fatty material, the suggestion 
was advanced that the Sacculina roots played the same part 
in the metabolism of infected crabs as is normally played by 
the ovary of a maturing female crab, and that the alterations 
in the secondary sexual characters of infected crabs followed 
as a consequence of this fat-forming activity of the Sacculina 
roots. 
It is proposed in this study to attempt to get a clearer con- 
ception of the activity of the Sacculina roots and of the effect 
they exert on the storage of food material in the host by the use 
of two chief methods : firstly, by employing certain micro- 
chemical reagents for the detection of different fat combina- 
