138 



THE VITAMINES 



extracted meat and fat in order to study osteomalacia and the effect 

 of a calcium-poor diet. The experiment lasted 126 days. Hebrant 

 and Antoine (406) described a typical osteomalacia in dogs. Gue'rin 

 (407) observed rickets in young dogs fed on meat, while animals from 

 the same litter, which were suckled, remained unaffected, Some of 

 these experiments were made not only with a vitamine-poor but also 

 with a calcium-poor diet and the pathological condition described 

 was nothing but osteoporosis. To this category, belongs the work 

 of Roloff (407a) in 1879, and also the communication of Reimers 

 and Boye (407b). Bull (408) described a severe occurrence of rickets 

 in young dogs fed on cooked meat and pollard, in Adelaide, Australia. 

 However, the systematic investigations of Mellanby (I.e. 95) are 

 of chief interest in this chapter. This investigator fed young dogs 

 5 to 8 weeks old on diets of various composition, poor in vitamine A. 

 These diets were more or less suitable for the production of rickets 

 and in the end, the following were chosen for this purpose. 



Some 200 dogs were used in this work; at first, they were kept on 

 the diet for 6 months but later, a shorter time, for it was demon- 

 strated that dogs on diet B developed rachitic symptoms after 6 

 weeks. Mellanby investigated the behavior of various foodstuffs of 

 animal and vegetable origin, and found that those that are protective 

 against rickets are rich in vitamine A. Still, meat poor in fat had 

 some effect in delaying the onset of rickets. Quickly growing dogs 

 develop rickets soonest, which apparently shows that the more 

 active the growth the more vitamine A is necessary. 



Symptomatology. The ossification of the bones proceeds in an 

 abnormal manner; hence the bones bend and the ligaments become 

 loose, making the deformities even more apparent. Swelling of the 

 epiphyses of the bones was easily noticeable and according to the 

 severity of the condition, deformities of the thorax developed with a 



