PRINCIPLTCS OF VETERINARY SURGERY 327 



temperatures of 27 degrees C were those whose riders were 

 as much concerned about their animals as about themselves; 

 they rifled the thatched roofs of cottages in order to get 

 them a little coarse mouldy straw. 



As a general rule the southern breeds resist cold better 

 than the horses from the north. In the Crimea, during the 

 Franco-English expedition, the Barbary and Arab horses 

 resisted better than the English horses, and the winter of 

 1870-1871 killed more English than African horses. The ox 

 sometimes exhibits frost-bites on the extremities, on the 

 scrotum and on the udder. Robeis observed an epidemic 

 gangrene of the nipples of a cow that he connects with the 

 effect of cold. The dog is not exempt from the same acci- 

 dent. Hunting dogs, from running on the ice, sometimes 

 exhibit frost-bites on the paws and ears. In birds frost-bites 

 of the feet and comb often occur simultaneously. 



Every species of animals do not offer the same resistance 

 to cold. The- rabbit endures temperatures of 10, 15 and 25 

 degrees C, without undergoing any apparent diminution of 

 animal heat. The sheep and the hog also possess great 

 powers of resistance, while the dog and the horse show far 

 more sensibility to cold. 



PATHOGENESIS.— By what mechanism does cold 

 cause organic troubles? It provokes a backward flow of 

 blood toward the large veins and the heart. The cutaneous 

 vaso-constriction which is nature's self-defense against cold, 

 is a remedy that is often more terrible than the injury it 

 aims to combat — coldness. The blood flows from the peri- 

 phery and flows toward the center of the body and a?cumu- 

 lates in the parenchymatous organs and clogs them. The 

 blood corpuscles are piled up and crammed into the lungs, 

 which then become the seat of a congestion so intense as to 

 prevent normal hsematosis. The respiration is accelerated 

 and painful and asphyxia may supervene. 



