VITAMINES 235 



one to which they are more susceptible differing in the case of 

 different animals. 



The vitamine responsible for the prevention of beri-beri is 

 quite distinct from that which inhibits scurvy. The anti-beri- 

 beri vitamine is more stable ; it is not destroyed by heat, and 

 can be treated with alcohol and ether without losing its virtue. 

 Certain foodstuffs, such as yeast, oats, and barley, which are 

 rich in anti-beri-beri vitamine, do not contain any anti-scurvy 

 vitamine. 



Rickets 



Rickets is another common disease found in all parts of the 

 world, and especially in the temperate zone, which is undoubtedly 

 due to a lack of some material in the diet, probably of a vitamine 

 nature. The disease has been attributed to deficient clothing, 

 to deficient fresh air, to indigestion, to syphilis, and to inherited 

 tendencies. But it is not inherited, not due to syphilis or any of 

 the evils I have mentioned. They are possibly predisposing 

 influences, but they cannot be considered as actually responsible 

 for the disease. The vast majority of the cases of rickets may 

 be directly traced to defective feeding ; indeed, we may say that 

 a faulty diet is the common and, in most cases, the sole source 

 of the mischief. And just as scurvy produced by a scorbutic 

 diet is cured by change of diet, so here a suitable change of diet 

 is attended by an arrest of the rickety condition and an oppor- 

 tunity is afforded for Nature to bring about restoration to 

 health. 



What is the substance the omission of which from the diet 

 leads to the outbreak of rickets ? The most striking feature of 

 the disease is the weak bones — the evident failure of the ossifica- 

 tion process — and this led to the view being expressed and long 

 entertained that the cause of the disease was a deficiency of 

 calcium or lime salts in the food. Investigation has however 

 shown that this is not really the case. Feeding animals with 

 food deficient in lime salts certainly leads to weakness in the 

 bones, but the rickety symptoms are otherwise absent. More- 

 over, there is conclusive evidence that rickets ma}', and often 

 does, develop when there is an abundance of lime salts in the 

 food. Rickets is quite common in limestone districts, and yet 

 the drinking water may be loaded with lime salts, and the 

 children living on patent foods made up with such drinking 



