740 



THE CIRCULATION. 



Now it is evident that the object should be, when there is such 

 disturbance, to equalize the circulation again, or force it back to 



its natural chan- 

 nels as quickly 

 as possible, and 

 that treatment 

 by which this 

 can be done 

 most easily and 

 quickly will be 

 the best. The 

 circulation is 

 really controlled 

 by the nervous 



FIG. 631. Portion of the web of a frog's foot, largely magni- System. If the 



fled, after a drop of strong alcohol had been placed upon nervOUS system 



it. The black spots are caused by the congestion j s from any 



induced by the alcohol. ^^ weakm . 



ed, so that it is unable to act with the usual vigor, there is less 

 ability to resist the influence of disturbing changes, and the horse 



J 



FIG. 632. Irregular contraction of small vessels in the web of a frog's foot 

 after the application of stimuli. 



is, as it is termed, more liable to take cold, which means a disturb- 

 ance of the circulation. 



Hence a horse, when warm and exhausted after a drive, if 

 given a little too much cold water would be liable to have colic, 



