594 Veterinary Medicine. 



Damp soils should be named in this connection. These not 

 only chill the air by evaporation, and condense the cold dews at 

 night, contributing to produce the extremes of hot noon day and 

 cold night temperature, with corresponding disturbances of the 

 bodily health, but they favor the preservation of the infinitesimal 

 forms of life (bacteria, protozoa) and therefore of the hypothet- 

 ical microbe of the disease. 



City life is a most potent cause. Berns tells us that hundreds 

 of horses die yearly in Brooklyn of osteoporosis, and that if sent 

 early to the country a large proportion recover. The same is true 

 of New York City and Philadelphia. Of Cincinnati, Meyer says 

 that he has failed to find a case more than five miles outside the 

 city limits, and that cases sent to the country make a partial or 

 complete recovery. If returned to their former city stables, nearly 

 all contract the disease anew within a year. 



Many cases, however are found in the country and often with- 

 in a circumscribed area. These indicate, as in the city cases, a 

 localized cause, bacteridian or otherwise. 



Early life predisposes, the majority of cases taking place before 

 the sixth or seventh year, yet the disease occurs at all ages up to 

 twenty years and over. 



Breed does not seem to make a material difference, and though 

 Shetland ponies have acquired a bad reputation, their propensity 

 to become fat and soft, their too often idle, pampered life, and the 

 confined quarters in which they are frequently kept, account for 

 much of the mortality. 



Asses and mules habitually escape, even in the South, where the 

 latter animal is so numerous and often so poorly kept. In Hine- 

 bauch's millet disease, the mules suffered more than the horses. 



Breeding horses, male and female, have often acute attacks and 

 die early. The drain on the system and confinement seem to act 

 injuriously. 



Nature. Until we know the essential cause or causes of osteo- 

 porosis, we musfbe in doubt as to its pathology. We are even de- 

 barred from pronouncing authoritatively upon the essential iden- 

 tity or difference of the various forms of softening, or rarefaction 

 of bone. In obedience to the cHnical manifestations and struct- 

 ural changes, rachitis, fragilitas osseum arid osteoporosis have 

 been separately described, but we cannot positively say that they 



