584 PRINCIPLES OF VETERINARY SURGERY 



ses unite. Some species, — pups and pigs, — are specially pre- 

 disposed to the affection. It is more frequent among the 

 highly developed breeds. The Newfoundland and Great 

 Dane dogs and the English breeds of hogs are particularly 

 susceptible. 



Heredity, by transmitting a special mode of nutrition, 

 predisposes toward insufficient calcification of the osseous 

 tissue. In the hog the entire litter is usually attacked, leav- 

 ing the impression that the process of ossification is vitiated 

 because of defective hygiene and alimentation. Lafosse at- 

 tributes its frequency in the hog to the permanent housing 

 of sows in unhealthy, cold, moist, dark and badly venti- 

 lated places, and to insufficient and deficient nourishment, 

 which produces a dearth of phosphates in the milk supply. 

 Captivity seems to provoke rachitis in the offspring of ani- 

 mals kept in menageries — lion's vvhelps, young tigers, pan- 

 thers, apes, etc. 



The relations existing between alimentation and rachi- 

 tis have frequently been mentioned. Premature weaning, 

 uniform and exclusive diet, dearth of mineral substances in 

 the food, and acid food are supposed to be potent factors, 

 and facts of observation and experience have been advanced 

 in support of this opinion. The import of this cause is em- 

 phasized by all observers. The disease has been found to 

 develop in pigs fed exclusively on raw potatoes, in calves 

 nourished by mothers suffering from osteomalacia, and in 

 young lions and panthers fed only upon meat. Roloff no- 

 ticed it in lambs and pigs suckling mothers nourished with 

 food containing a dearth of lime salts. J. Guerin produced 

 the disease in two pups, one month old, by feeding them 

 only with meat, but the experiment is not convincing, be- 

 cause it is not accompanied with data as to the lesions 

 presented at the autopsy. 



The disease was experimentally produced by Letellier, 



