62 



Scientific Proceedings (31). 



terious influence on the animal organism, that effect is not ordi- 

 narily an immediate one, but rather the slow perversion of organic 

 function induced by chronic misuse. Again, if benefit results from 

 a special diet under any condition, time may be required to make 

 that benefit clearly distinguishable. The dogs used in these ex- 

 periments were under daily observation for periods of at least two 

 months and in several cases for four months before inauguration 

 of the pathological phase. 



In testing the physiological resistance of the dogs in these 

 experiments, use was made of two methods : (i) hypodermic in- 

 jection of the toxin, ricin ; and (2) the withdrawal of definite 

 amounts of blood from one of the large arteries. Ricin was 

 selected because it produces some symptoms which are analogous 

 to those of acute infections, namely, fever, cardio-vascular embar- 

 rassment and marked prostration. As in the case of infections, 

 ricin also causes noticeable stimulation of metabolism, as is shown 

 by the increased ehmination of nitrogen and sulfur after its injec- 

 tion. The disadvantages in its use are that immunity quickly 

 arises and that the material is so very toxic that no latitude is per- 

 mitted for minor individual peculiarities in animals. By experi- 

 ment I milligram per kilo was found to be the maximum non- 

 lethal dose for the commercial sample used. 



Experiments with Ricin. 

 Six dogs were subjected to inoculation with ricin. Of these, 

 three were on a high plane of protein nutrition, the daily amount 

 of food containing uniformly in each case 1.4 to 2.0 grams of N 

 per kilo of body weight. After inoculation with ricin (i mg. per 

 kilo), all of these three specially well-fed animals died. A fourth 

 dog was on a medium plane of protein nutrition, i.i gram, of N 

 per kilo, and this dog survived the inoculation. Of the two remain- 

 ing animals of this group, both on a low plane of protein nutri- 

 tion, one died and one survived. The dog which survived received 

 the protein equivalent of 0.35 gram of N per kilo of body weight 

 during the experimental period and the one that died, 0.37 gram 

 of N per kilo. 



In order to test the effect of exercise, the former of these two 

 dogs, after the completion of the above mentioned experiment, was 



