OBJECTS OF DRINKING WATER. 129 



University of Wisconsin, 1899), wn o have shown by experi- 

 ment that horned cattle suffer a loss of temperature of from 

 ij4 F. to 3 F. by drinking ordinary cold water when they 

 are at rest ; but only one of less than }4 F. by drinking 

 water which has been raised to 101 F. (the approximate 

 temperature of their bodies). In this case, the fall in tempera- 

 ture of somewhat less than J^ F. may be attributed to the 

 effect of increased evaporation. It appears that up to the 

 present, no experiments have been made to show the cooling 

 action by evaporation which water recently drunk, has on the 

 system, when the bodily temperature has been considerably 

 raised by exercise. We may, however, conclude from experi- 

 ence, that in such cases, the ingestion of water is a strong 

 stimulus to evaporation. 



3. To assuage thirst, which, apart from artificial stimulation 

 (for instance, by an excess of salt in the food), is as a rule 

 proportionate in intensity to the need the system has for 

 water. 



4. To aid in excretion. The blood requires water as much 

 for removing waste and injurious products out of the body, as 

 for nutrition. Among these deleterious substances we have 

 nitrogenous compounds which give rise to the feeling of 

 fatigue (p. 56) ; and, if retained too long in the system, to 

 nervous depression and to rheumatic affections. As they are 

 sparingly soluble in water, their due removal demands a free 

 supply and a free excretion of water. I am inclined to think 

 that continued restriction in the quantity of the drinking 

 water, is a not uncommon cause in horses, of obscure cases 

 of lameness which are usually thought to be joint rheumatism 

 or navicular disease. The presence of water in the body 

 stimulates change of tissue and aids in the removal of carbonic 

 acid. Hence it is specially necessary during hard work. 



Water also plays an important part in excretion by mecha- 

 nically aiding the intestines to get rid of the residue of food 



9 



