34 



Scientific Proceedings (6i). 



the usual way, and the diagnosis confirmed microscopically by 

 Professor G. Y. Rusk, of the department of pathology. In 

 addition, seven rats were inoculated with pieces of a metastatic 

 tumor from the mediastinum, and in fourteen days all had de- 

 veloped well-marked tumors. 



Two facts seem evident. The tumor has again become a 

 metastasizing tumor, and treatment with cholesterol has increased 

 that tendency. The results from the treatment with cholesterol 

 were to be expected from our former experiments. Why the tumor 

 should spontaneously become more virulent (if we look upon the 

 formation of metastases as an index of virulence) is not so clear. 

 Haarland 1 has shown that mice transferred from Berlin to Christi- 

 ania became refractory to Ehrlich's sarcoma, and explains it as 

 due to change of diet from fats and proteins, to carbohydrates. 

 This is in accord with the results of Van Alstyne and Beebe, 2 

 who find a non-carbohydrate diet of casein and lard reduces both 

 the number of "takes" and the growth of the tumor. On the 

 other hand, Danysz and Skszynski 3 found a greater number of 

 "takes" in animals fed on a vegetable diet, than in those fed on 

 meat. Sweet, Corson-White and Saxon, 4 using the Osborne- 

 Mendel diet, which contains plenty of carbohydrate, found a 

 retarding influence. Our rats have been fed the regular laboratory 

 diet of rolled barley, bread, meat, and occasionally lettuce, of 

 which they seem to be very fond. It would seem, then, rather 

 difficult to explain this change in the tumor on the ground of a 

 change in diet. 



As to the strain of rats used, they were obtained from New 

 York, and were all over one year of age. This fact may be 

 significant. 



There is another possibility that might be tentatively con- 

 sidered, namely, that in all these results of experimental diets 

 we may be dealing with a common factor. If, as has been sug- 

 gested, cholesterol is a cleavage product of some of the proteins, 

 it may be we shall find here an explanation of some of the varying 

 results of investigators. The diet used by Sweet, Corson-White 



1 Haarland, Berl. klin. Woch., Vol. 44, 1907, p. 713. 



2 Van Alstyne and Beebe, Jour. Med. Research, Vol. 29, No. 2, 1913. P- 2I 7- 



3 Danysz and Skszynski, Compt. Rend, de Soc. de Biol., Vol. 74, 1913, p. H44- 



4 Sweet, Corson- White and Saxon, Jour. Biol. Chem., Vol. 15, No. r, 1913. P- 



