448 Veterinary Medicine. 



It is not necessary to ignore the action of cold as a concurrent 

 factor in certain cases, or as a stimulant to reflex vaso-motor 

 paresis, to muscular metamorphosis and the increase of haemo- 

 globin in the blood. It is only necessary that this should be 

 held as subordinate and non-essential to the final result. Several 

 other factors that are accorded a subordinate place by these 

 writers, are so constant and so manifestly essential that they 

 must be allotted a much more important position in the list of 

 causes. 



A period of rest is a constant precursor of an attack. The 

 more extended the inquiry the more certain we become that a 

 short rest is a prerequisite to equine haemoglobinsemia. The 

 horse that is kept at daily steady work may be said to be prac- 

 tically exempt. Even the non-professional observer recognizes 

 the fact and names the disease after the weekly or yearly holiday 

 or rest day which was the occasion of it. To him it is the Mon- 

 day morning disease, the disease of the day following Thanks- 

 giving, Christmas, New Year, or Fourth of July. It is the dis- 

 ease of wet weather, of heavy snowfalls, of the blizzard, or of 

 the owner's absence from home, of any time that entails one or 

 two days of absolute inactivity in the stall. 



But again the affection does not appear in the horse that is 

 absolutely idle for a length of time. It is the short period of 

 rest in an interval of otherwise continuous work that deter- 

 mines it. In short the subject must be in good muscular condi- 

 tion and with a hearty, vigorous appetite and good digestion. 

 The short unwonted rest interrupts the disposal of the rich 

 products of a vigorous digestion, and tends to overload the portal 

 veins, the liver, the blood and tissues with an excess of proteids. 

 The condition of the animal is so far one of plethora. 



Another feature that bears this out is that the attack comes 

 only in the animal that is heavily fed on a strongly nitrogenous 

 ration. It is not the disease of the horse kept on straw, or 

 hay, or which receives a limited amount only of grain. It does 

 not occur in the animal which has its grain suspended or materi- 

 ally reduced during the one or two days of idleness. It does 

 not select the horse that has had a laxative either in the form of 

 food or medicine. This last may increase the sensitiveness to 

 cold, but it certainly lessens the tendency to haemoglobinsemia. 

 The most rational explanation appears to be that it affords this 



