18 



solution, distilled water, or hrotli, the dcni-cc ol" iiiactiva- 

 tiou decreasing in the order given, lie then cxixMiincuted 

 with dilutions of 1-10 and 1-1000 of tlie slock filtrate and 

 found lliat an increased dilution with salt and Locke's 

 solution increased the percentage of phage inactivated 

 while, on the coiiti'ai'N', increased dilution with distilled 

 water or brotii did not. 



According to Stockman and Minett (li)2G), the virus of 

 foot and mouth disease was not destroyed by repeated 

 freezing in ammonia brine. 



Pictet and Yung (1884) reported that the cow-pox vac- 

 cine was inactivated after two consecutive exposures of 

 respectively 108 hours to - 70° and 20 hours to - 130°. 



According to Barrat (1903), an exposure of the rabies 

 virus to the temperature of liquid air for 1 to 5 hours did 

 not inactivate it. 



Salvin-Moore and Barrat (1908) found that a stay of 

 30 minutes in liquid air did not affect the graftable mouth 

 cancer. 



Gaylord (1908) obtained identical results with the 

 same material maintained in liquid air for 80 minutes. 



Rivers (1927) observed that the herpes virus in a brain 

 emulsion was not inactivated by 12 freezings in liquid air 

 ])ut was inactivated when frozen 24 times in an emulsion 

 diluted 1-20 or more with Locke's solution. 



Similar results were obtained by the same author with 

 vaccine virus, which resisted 12 freezings in a testicular 

 emulsion diluted 1-10, 1-100, and 1-1000, Imt the titer 

 of the virus decreased after 24 freezings at. dilutions of 

 1-10,000 and 1-100,000 and the virulence was completely 

 destroyed after 34 freezings at a dilution of 1-100,000. 



Rivers investigated also rims III and found it to be 

 readily inactivated after 12 freezings at dilutions of 1-10 

 of his stock emulsion. 



The results on the infracellulars can be summarized 

 as follows: 1. The enzymes, toxins, bacteriophage and 

 viruses investigated are not affected by a freezing of their 



