GROWTH AND NUTRITION 



89 



made a report on the children in an infant asylum in New York 

 City and noted a high incidence of this disease. 



As there is a geographical distribution, there is also a seasonal 

 incidence. Hansemann 32 noted that children dying in the fall 

 are comparatively free of rickets while those dying in the spring 

 usually manifest certain symptoms of it. 



According to a citation by Park 33 the disease is common in 

 pigs, lambs, kids, and puppies, but occurs less frequently in 

 colts or calves. 



For many years the cause of rickets was in dispute. It has 

 been attributed to inheritance, to bacterial infections, to glut- 

 tony, and to disturbances in 

 the endocrine glands. Mel- 

 lanby 34 was the first to sug- 

 gest that certain fats exert a 

 protective function in bone 

 development. He observed 

 rachitic development in the 

 long bones of dogs, in the 

 epiphyses, as indicated by 

 X-ray photographs, but 

 when butter or cod-liver oil 

 were included in the diet, ra- 

 chitic changes were not noted. 

 According to Mellanby, vita- 

 min A, or some substance 

 with similar distribution, has 

 a distinct antirachitic effect. 



McCollum, Simmonds, Shipley, and Park 30 presented definite 

 evidence that vitamin A and the antirachitic substances are dis- 

 tinct. The diets used were low in calcium and about the optimal 

 in phosphorus. He noted that butter fat was of little value as a 

 protection against rickets, but cod-liver oil was potent, even in 

 small quantities. 



Before leaving the subject we should state that the subject of 



Figure 55. Cod-liver oil may prevent rickets. 

 Note that the bones on the left are not cal- 

 cified in the growing regions. After Rosen- 

 heim and Webster. By permission of the 

 Biochemical Journal and the Cambridge 

 University Press. 



