150 THE VITAMINES 



occurred not infrequently. In the bones, on the contrary, at least 

 microscopically, no changes were found. 



Etiology. We may well imagine that because of the great practical 

 significance of this disease no effort has been spared to discover its 

 cause. One of the older theories of Theiler (I.e. 439) assumed the 

 presence of toxins in the grass. This theory was experimentally 

 tested by Viljoen (441) in that he fed a series of animals on 

 various kinds of grass, found in regions affected by lamziekte, with 

 negative results. The theory of infection was tested by Spruell 

 (442); cows and goats received intravenous injections of the blood, 

 lymph glands and ascites fluid of sick animals; here too, the experi- 

 ments proved to be negative. Mitchell (443) and Walker (444) 

 sought to bring about the disease in healthy animals by using carcass 

 material of lamziekte animals, but in vain. We formerly held that 

 lamziekte was similar to beriberi, but this view was modified by us 

 in 1915 (445), in that we considered it to be similar to rickets. 

 This view is also held by Hart, Steenbock and Hoppert (445a), who 

 arrived at this conclusion from experiments with goats. Here cod 

 liver oil had a distinctly favorable action on the calcium metabolism. 

 In spite of this, our first opinion was carefully tested, and Stead (446) 

 attempted to show that lamziekte was analogous to beriberi. He fed 

 pigs on meat obtained from animals which had died of lamziekte, in 

 the belief that it was poorer in vitamine B than normal meat. 

 Cattle were also fed on white rice, samp (a product made from 

 decorticated corn), white flour and oats; they showed pica, stiffness 

 of the legs and pains on walking. Theiler, Green and Viljoen (I.e. 

 278) have investigated a series of animal species, already mentioned 

 previously, as to their vitamine B requirements; horses, dogs, goats, 

 sheep and pigs were used. They were kept on a diet consisting chiefly 

 of white rice, and in no case was there any symptom characteristic 

 of beriberi. Cattle were kept on white rice for a year without the 

 appearance of any beriberi symptoms. In the worst case, symptoms 

 were noted, in accord with the findings of Stead, which were thought 

 of as laminitis and which could not be attributed to a lack of vitamine 

 B. Latterly, Stead seems to have abandoned his view in favor of 

 Theiler's. 17 One cow fed on white rice and autoclaved straw or 



17 Theiler said that no grass could be so poor in vitamine as was the diet 

 which he used and he believed, therefore, that it had nothing to do with an 

 avitaminosis. The survival of the animal, he attributed to a bacterial 

 symbiosis (p. 75). 



