DiETKTu; l)KFI^IF,Nc^■. 303 



Scitrz'y, the earliest of the diseases recognised as dietetic in 

 origin, has been long regarded as a type of " deficiency disease " 

 arising wherever a supply of frcsli food became unavailable. It 

 was most prevalent amongst sailors on long sea voyages in the old 

 sailing vessels, and victims which siu'vived to reach port were 

 found to be curable by change of diet to foods such as vegetables, 

 fresh meat, fnn"t ancl fruit juices. So far back as 1795 a lime- 

 juice ration was introduced into the English marine service as a 

 preventative measm-e against scurvy. In the first Scott Ex])edi- 

 tion to the South Pole an outbreak of scurvy occurred, btit this 

 disappeared again as soon as fresh seal meat became available. 



The theories in regard to the causation of scurvy have been 

 various. The phosphorus deficiency theory of five or six years 

 ago has now given place to the avitaminosis hypothesis, and 

 scurv}' is now regarded as due to the lack of a vitamine, analo- 

 gous to the beriberi vitamine, but more easily destroyed, and 

 therefore more likely to be lacking iu ]:)reserved foods. 



Barloiv's Disease, or infantile scurvy, has been attributed to 

 the use of sterilised milk and artificial " baby-foods." 



Pellagra, a disease characterised by erythema, stomatitis, 

 gastro-enteritis, and degenerative alteration of the central 

 nervous system, and occurring chiefly in the countries where 

 maize is the staple cereal, is held by Funk to be associated with 

 the consumption of maize in much the same way as beriberi is 

 with that of rice. The disease is most prevalent in Northern 

 Italy, Roiunania. Southern Tyrol, and Northern America. 



Several other liypotheses have been ])ut forward to account 

 for its occurrence, including an intoxication theory, an infection 

 theory, a " photodynamic " theorv, in which the malady is held 

 to be due to an increased sensitiveness to light on the part of the 

 patient, brought about bv the presence of toxic light-sensitising 

 bodies in sjioiled maize, and, most recently of all, a rather vague 

 theorv which attributes pellagra to the ])resence of collodial silica 

 in the drinking water. 



On the whole, the evidence for any one theory' is not conclu- 

 sive, and at the ])resent day the infection theory still seems to 

 claim the majority of adherents. 



Rickets and Osteoinalacia. — For these two diseases, in which 

 bone lesions j^resent one of the most characteristic features of 

 the trouble, the vitamine-hunger theorv has also been advanced. 

 The supporters of the theory are, however, few as yet. and we 

 may therefore omit these diseases from the discussion. 



Within the last few years the vitamine hypothesis has been 

 boomed to such an extent that a tendency is sometimes shown to 

 bring as yet unexplained diseases within the category of the avi- 

 taminoses, whether the evidence really justifies it or not. 



C^ne of the difficulties in the way of explaining a variety 

 of diseases on the same hypothesis lies in the fashion in which the 

 hypothesis has to be stretched beyond the experimental evidence 

 which gave it birth. In the case of the vitamine theory, the 



