92 PATHOLOGY. 



or destructive process, and the primary digestion, or compensating 

 process. 



It is very true that a healthy animal will retain its appetite 

 and be capable of partaking of food and digesting it for a con- 

 siderable time without exercise, and, under certain circumstances, 

 which sometimes seem inexplicable, remain in health. Gene- 

 rally, however, the excessive amount of nutriment is stored up 

 amongst the fatty tissues in various organs ; and the storage of 

 fat may so far be looked upon as an act of excretion, bearing out 

 the proposition of Treviranus, that " each single part of the body, 

 in respect to its nutrition, stands to the whole body in the 

 relation of an excreted substance ;" or, in other words, every part 

 and tissue of the body, by taking from the blood the peculiar 

 substance of which it is made, or which it can accommodate and 

 store for future use, acts as an excretory organ, inasmuch as it 

 removes from the blood that which, if retained, would be in- 

 jurious to the rest of the body. 



In many cases, however, this act of accommodation, as it may 

 be termed, is insufficient ; and in animals fed upon rich food, par- 

 ticularly nitrogenous food, the blood-mass becomes so impure, 

 from the presence of effete materials, that the whole body is 

 poisoned. For example — and this not at all uncommon — a 

 horse is kept in the stable for some days, perhaps three or four 

 days, and fed upon its usual liberal allowance of food, con- 

 sisting of hay, corn, and water. When put to its work it 

 usually commences its labour with the greatest spirit and ani- 

 mation, every nerve and muscle being, as it were, in the highest 

 state of functional perfection ; but before it has proceeded more 

 than a few miles on the journey, very often before it has gone a 

 mile, it suddenly staggers and falls paralysed. Sometimes it 

 may be able to rise and walk slowly to its stable ; sometimes it 

 never rises again. Shortly after the attack it is observed to 

 pass large quantities of a dark coffee-coloured urine, so dark, 

 indeed, as to lead many observers to suppose that it is blood. 

 Careful observations have, however, enabled me to determine 

 that such urine contains no blood, and little or no albumen, but 

 that the darkness of its colour depends upon an excessive 

 quantity of colouring matter, urea, and probably other pro- 

 ducts of the degradation of the nutrient materials which had 

 accumulated in the blood-mass during the period the animal 

 was at rest. 



