Influence of Cholesterol on Tumors. 43 



batical leave. Two sets of experiments were made, and may be 

 briefly described. 



Experiment 1. — Seventeen rats that had proved refractory to 

 inoculation in April last (1913) were injected with 1 c.c. of a 2 

 per cent, emulsion of cholesterol in sodium oleate, on August 4 

 and 6, 1913. The injection was made on the left side. On August 

 6 they were all inoculated on the right side with the eighth genera- 

 tion of a Flexner-Jobling tumor. The injections of cholesterol 

 emulsion were continued every alternate day thereafter, on the 

 left side. On August 27, twenty-one days after inoculation, eight 

 rats had developed tumors, ranging from 5 X5 mm. to 13 X 15 mm. 

 in size, the average for the eight being 9.7 mm. Bearing in mind 

 that rats previously refractory may later become susceptible, and 

 that tumors vary in virulence, this is not conclusive. The mistake 

 was in not setting aside some of this lot as controls. 



Experiment 2. — Forty "Chicago" rats were divided into two 

 lots of twenty each. Lot A were injected with 1 c.c. of a 2 per 

 cent, cholesterol emulsion on the left side, on August 11 and 13, 

 1913. August 13 both lot A and lot B were inoculated on the 

 right side with portions of the same Flexner-Jobling tumor, eighth 

 generation. It may be said in passing that this is the same strain 

 of tumor used by us in our original experiments on the "Chicago" 

 rats. 1 Lot A was then injected with 1 c.c. cholesterol emulsion 

 every alternate day until September 3, 19 13. Lot B were left 

 untreated as controls. On September 3, twenty-one days after 

 inoculation, thirteen rats in lot A had developed tumors ranging 

 in size from 5 X5 mm. to 25 X 10 mm., the average for the thirteen 

 being 13 mm. Seven rats in lot B (controls) developed tumors 

 ranging from 3X3 mm. to 20X11 mm. in size, the average for the 

 seven being 9.5 mm. On September 15 the tumors were again 

 measured, with the following result. Seven tumors in the "refrac- 

 tory" lot (one had retrogressed) gave an average diameter of 18.5 

 mm. Six tumors of lot B (one retrogressed) averaged 8.41 mm. 

 Twelve tumors of lot A (one died) gave an average of 17.6 mm. 

 The cholesterol-treated tumors have steadily increased in size, 

 while the controls have just about held their own. Neither the 

 "refractory" rats, nor those of lot A received any cholesterol 

 after August 29. 



1 Lac. cit. 



