RICKETS. 265 



Rickets. 



Rickets is a disease of youth, namely, of a period of life during 

 which development of bone takes place. It is rare in the horse, 

 and is almost entirely confined to foals and yearlings. It also 

 affects children, monkeys, ruminants, rodents, marsupials, large 

 and small oats, bears, swine, dogs, seals, birds and probably all 

 other animals possessed of bones. Even shell fish are said to suffer 

 from it. " So frequent is it among quadrumana that half the 

 monkeys and lemurs brought to this country die rickety " {Bland 

 Sutton). 



NATURE AND CAUSES.— Rickets is a general disease in which 

 the principal manifestations are increased development of new bone 

 which is abnormally soft and weak,- and the formation of bony 

 tumours (eixostoses), especially about the joints. The existing bone 

 remains practically unchanged. The surface of the body is un- 

 usually sensitive to pressure. This disease appears to be caused 

 by deficiency, in the food, of salts of lime, or of want of power of 

 assimilating such salts on account of the absence, in the food, of 

 other constituents necessary to healthy digestion. Thus, Cheadle. 

 cites a case of most extreme rickets occurring in a child fed on 

 skim milk, and also the beneficial effect of cod liver oil. The cure 

 of rickets in the lion cubs at the Zoological Gardens, which were 

 fed only on horse flesh, by giving them ood liver oil' and pounded 

 bones with milk is a remarkable instance of the part played by an 

 improper diet in the production of this disease. A deficiency of 

 limejn the water of the district has also beer i RtatpH t.n bp, a. cause 

 of this disease, but this is evidently not the case, for rickets is 

 far more common in London, which is supplied with water con- 

 taining a considerable amount of lime, than in Glasgow, where the 

 water contains merely a trace. In human practice, the urine of 

 rickety patients sometimes has an excess of phosphate of lime, 

 which is derived from the imperfectly digested food, and not from 

 tixe rickety bones. Rickets is essentially a disease of youth ; as it 

 is connected with the deposition of new bone. 



The ch ief causes of rickets in the horse _ are a supp ly of mi lk 

 de fective in qu ajiti ty or quality ; foo d which does not furnish a 

 sufficiency of salts of lime ; too hig h feed ing | and want of exercise. 

 All these causes may be intensified by insanitary conditions. 

 Hereditary influence in this disease seems to be confined to the 

 mare; for no part appears to be taken by the sire. Although it 



