144 THE VITAMINES 



pigs. This is so because few investigations in which only the vita- 

 mine factor is lacking, while all other factors are controlled, have been 

 carried out. All of the above-mentioned investigations are com- 

 plicated by mixed symptoms, and it is therefore impossible to form 

 an unbiased opinion as to the nutritive requirements of these animals. 

 This is all the more regrettable, since the pig, which eats anything, 

 is peculiarly adapted for the study of human nutrition. 



In 1907, Hoist and Frolich (I.e. 36) described, in rice-fed pigs, 

 symptoms which were thought to be mixed forms of beriberi and 

 scurvy. Since white rice is lacking in all three vitamines, it is impos- 

 sible to say which one is most important for these animals. Theiler, 

 Green and Viljoen (I.e. 278) on the contrary, could observe no 

 specific symptoms on this food. In one case, gall stones were found; 

 in others, enteritis was noted, which may perhaps be regarded as a 

 sign of an avitaminosis. Plimmer (422a) observed scurvy in pigs 

 fed on cooked food, the symptoms of which were relieved by the 

 administration of uncooked food. Green (423) carried out investiga- 

 tions with a diet poor in calcium, and in this way found two kinds 

 of undernourishment; one kind depends upon protein which was 

 qualitatively shown to be inadequate, while the second could be 

 attributed to insufficient protein and salts addition. The animals 

 were in poor nutritive condition and showed defective bone growth 

 with insufficient calcification. Substitution of lard by butter exerted 

 no favorable influence. It is one of the few investigations on the 

 nutrition of domestic animals, in which vitamine A was given special 

 attention. Another investigation, in which the presence of vitamine 

 A in the diet was provided for, was that of Hart, Miller and McCollum 

 (424) A typical composition of the diet used by them was 95.5 

 parts wheat meal, 2.5 parts wheat gluten, 2 parts butter, di-potassium 

 phosphate and calcium lactate. On this diet, the animals developed 

 symptoms quite similar to those of beriberi. Among other symp- 

 toms, pathological changes were noted in the spinal cord which 

 showed fatty degeneration. The symptoms made their appearance 

 after about 9 months, when a decrease in weight, difficulty of forward 

 motion, rough coat, labored breathing and muscle tremors were 

 observed. There was also stiffness of the extremities and dragging 

 of the legs; if the animals were helped to their legs they again sank 

 at the knees. Since McCollum, at this time, denied the existence 

 of vitamine C, the diet used was considered as complete, and the 



