324 THE VITAMINES 



pens in practice, the unfavorable hygienic conditions are associated 

 with a deficient dietary. Mann (1123) investigated statistically 

 1000 cases of rickets in London, together with 250 controls. His 

 results speak in favor of the dietetic cause of rickets, inasmuch as 

 he paid particular attention to the mode of nutrition. A critical 

 survey of his cases convinced him that: 



44 per cent of the cases suffered from a lack of fat and an excess of carbohy- 

 drates in the diet. 



16 per cent were breast fed by a poorly nourished mother. 



13 per cent occurred in families in straightened circumstances. 



6 per cent exhibited a mis-proportion between the dietary constituents, in 

 favor of the carbohydrates. 



Czerny (1123a) and Siegert (1123b) allot to heredity an im- 

 portant role in the etiology of rickets. That the cause for all rachitic 

 manifestations lies in the central nervous system, was assumed by 

 Pommer (I.e. 1064), and later by Schabad (1124), but this assumption 

 did not exclude the dietetic factor. Other dietetic theories are as 

 follows: 



1. Lack of fat and excess of carbohydrates; Herter (1124a); Holt 

 (1125); Cheadle (1126). 



2. Lack of a substance of an unknown nature in the diet; Hopkins 

 (I.e. 23). 



3. Lack of calcium in the food; Stolzner (1127). 



4. Excessively rich food; Esser (1128). 



5. Lack of organic phosphorus combinations; Schaumann (I.e. 2). 



6. Nutritional disturbances of every description, acidosis and 

 excessive nourishment; Pritchard (1129). 



7. Lack of antirachitic vitamine; Casimir Funk; Mellanby. 



The vitamine etiology of rickets 



This theory was first suggested by us and was attributed to the 

 lack of a specific antirachitic vitamine, in relation to which, the pres- 

 ence of such a vitamine in cod liver oil has been assumed. These 

 conceptions were first tested experimentally by Edward Mellanby (I.e. 

 95). In the discussion as to the vitamine requirements of dogs, we 

 have already touched upon his work. He divided the foodstuffs 

 used by him into two groups one, protective against rickets, the 

 other, not. 



