PHOSPHORUS STARVATION: I. 95 



the substances to be added counteract the damaging effect of the white rice. 

 I believe my experiments give sufficient proof at present that at least one 

 of the main factors in these protective substances must be an organic com- 

 pound of phosphorus, because of the fact that the addition of such 

 organic phosphorus, as it is present in the rice husk, has a protective 

 action against the damaging effect of the white rice itself. I agree with 

 the interpretation which Schaumann has given to his own experiments 

 and to those of Eykman. He may be correct in considering that the 

 nucleo-protein of yeast is the constituent preventing polyneuritis, but in 

 the case of rice it is my belief that the phosphorus compound which has 

 been designated as "phytin" is the active substance. 



Although my experiments seem to be sufficiently positive to warrant a 

 continuation along the same line, I have abandoned them at present in 

 order to discover if it is not possible to work with animals other than 

 chickens. These birds are not very appropriate for exact experimentation, 

 and while we can endeavor to produce in them such diseases as poly- 

 neuritis, it is very tiresome to carry on close feeding experiments with 

 fowls. I have therefore attempted to feed other animals on white rice or 

 on a food having a similar composition. 



Monkeys were fed on white bread made only of wheat flour and water 

 and salt. Such a bread, when fresh, contains about 40 per cent of water, 

 8 of protein, 52 of carbohydrates, 0.116 of P 2 5 ; or, if we reduce the 

 percentages to the same water content as rice, about 10 per cent of protein, 

 75 of carbohydrate and 0.155 of P 2 O . Therefore, this bread in its 

 P 2 0- content corresponds to a very highly polished rice; the protein 

 content is slightly higher, that of carbohydrates somewhat lower, but these 

 differences are really too small to be of any importance. 



The animals in the beginning took this bread readily. At first I 

 gave 75 and then 100 grams per monkey of 2,000 grams; this amount 

 being almost entirely eaten up each day, up to the time, when the monkeys 

 became very weak. This amount of bread corresponds to 100 calories per 

 kilo of body weight. It must be remembered that the demand for energy 

 in these animals is very great when we consider their small size, great 

 surface and their excessive muscular activity. The animals (Macacus 

 philippinensis Geoff.) were kept in a large, airy yard, covered on top and 

 on one side with wire gauze, thus giving them plenty of air and more space 

 for free movement and gymnastic exercise than is found in the usual 

 cages. Furthermore, the animals were placed at least two in a room so 

 that they would not feel their imprisonment quite so keenly. In work- 

 ing with monkeys this point must not be forgotten. 



