STUDIES IN THE EXPERIMENTAL ANALYSIS OF SEX. 291 
from its fat-link, and the combined fat-link + fatty molecule- 
is broken away from the liv^er and floats freely in the blood. 
AVe suppose that this process occurs in the normal metabolism 
of the animal. 
Now, when the Sacculina roots begin their activity they 
seize on the fatty molecules in the fat-link + fat combina- 
tions which are free in the blood, as shown on the left-hand 
side of the diagram, and in so doing they liberate large 
numbers of free fat-links. These free fat-links, with an uii- 
satisfled affinity for fat, travel again to the liver, where they 
flv themselves onto fresh fat-molecules in the liver, as shown 
in the middle part of the rig'ht-hand side of the diagram. 
Now, this process of constantly fixing* on the fat-molecules 
of the liver leads to a regeneration in excess of the fat side- 
chains in the liver, and as more and more fat-links from tlie- 
proteid molecules attach themselves to these regenerated fat 
side-chains, the process goes on in an ever-increasing ratio. 
The result of the process will clearly be to flood the blood 
with a large number of fat-link + fat combinations and of 
free fat-links, so that the total composition of the blood will 
be materially affected. It may be urged in criticism of this 
theory that it is fanciful and artificial, but though we are far 
from claiming that the representation of the facts by our 
symbols approaches the chemical reality, yet we have actual 
evidence in fact for each step of the process. 
We may, of course, replace the Sacculina roots on the 
left-hand side of the diagram with the ovai*y of a normal 
female crab, and in this case we have actual evidence of the 
alteration of the composition of blood during the growth of 
the ovary in the flooding of the blood by lutein and fat, which 
has been shown to occur. 
Now, we know from a variety of evidence that the develop- 
ment of certain secondary sexual characters depends for its 
stimulus on substances carried about the body in the medium 
of the blood or body-fluids. If, then, our conception of the 
action of the Sacculina roots or ovary is correct, we have^ 
shown how they can produce substances in the blood and 
