Inclusion of Carmine Particles by Sarcoma Cells. 117 
into the blood circulation in a majority of cases lose their pro- 
liferating power. Ehrlich's opinion that the most virulent tumors 
do not form metastasis also seems to be correct, as no meta- 
stasis was formed after the injection of the most virulent sarcoma 
of the rat. But the athreptic theory does not explain this fact. 
None of these animals had any sarcoma growth anywhere and 
consequently the sarcoma cells introduced into the circulation 
could find all the necessary specific food. 
The most interesting phenomenon observed in the course of 
these experiments consists in the fact, that while the Flexner tumor 
found lodgment in the lungs after an intravascular injection, the 
mouse sarcoma produced metastasis only in the liver. It would 
seem that the different topographic distribution of metastasis in 
the different kinds of malignant tumors is due not so much to the 
difference in the channels through which the cancer cells are trans- 
ported, and which were identical in all experiments reported here, 
but to a specific affinity between cancer cells and cells of certain 
organs. The comprehension of this specific affinity between a 
cancer cell and a particular part of the organism of the host may 
be helpful in elucidating many factors in the genesis of tumors 
and will be the main object of the further study of the experimental 
metastasis formation by the writers. 
