382 A MANUAL OF VETERINARY PHYSIOLOGY 



once they go to the stud, live in the open for the remainder 

 of their lives, and never wear a blanket. And practical ex- 

 perience tells us that this may be gradually imposed on all horses 

 with impunity, even those which have been kept in hot stables. 

 Coughs, colds, and inflammatory chest affections, usually 

 attributed to cold, are" practically unknown among horses living 

 in the open, even during the coldest weather, and it is easy to 

 show that these diseases are largely the result of the artificial 

 conditions under which working horses have to live. 



Fig. 108. — Ponies living in the Open in the Arctic Circle, at 45 F. 

 below Zero (Jackson). 



Jackson* has proved that the law of adaptability which applies 

 to men living in the Polar regions applies with equal force to 

 horses ; for two and a half years he kept horses at 8o° north lati- 

 tude. During this time the thermometer never rose higher than 

 n° F. above freezing, while 70 to 8o° F. below freezing were com- 

 mon temperatures. During the sleighing expeditions these animals 

 lived in the open, and wore one blanket, which, as may be seen in 

 Fig. 108, found its way where most blankets get, under the hind- 

 feet. At the time the photograph was taken the animals were 

 in a temperature of 45 F. below zero at night — viz., as far below 

 freezing-point as summer heat is above it. It is interesting 

 to note they did not surfer, and Major Jackson informs the writer 



* ' A Thousand Days in the Arctic,' F. G. Jackson. 



