Dietary Conditions on Physiological Resistance. 65 



the same litter. These animals were half-breed Scotch terriers, 

 about two years old, that had lived together under the same con- 

 ditions until they were brought to the laboratory. One was grad- 

 ually accustomed to a diet containing only 0.2 gram of N per kilo, 

 the other to food containing 0.8 gram of N per kilo. As a matter 

 of further interest the opsonic index of these dogs was several 

 times estimated, using Staphylococcus aureus that had been ren- 

 dered pathogenic to dogs. This index was, and remained, the 

 same for both animals. The final hemorrhages were survived by 

 both animals and, so far as one might estimate, about equally well. 



The accompanying tables present an outline of the experi- 

 ments and show details not mentioned above. 



