CHLOROFORM. 605 



Chloroform 



is the best agent for producing general insensibility in horses 

 during surgical operations. To- prevent it from becoming de- 

 composed, it should be kept in glass stoppered bottles in a cool 

 place and covered with blue paper. 



USES. — The uses of chlorofonn are : (1) To produce insensi- 

 bility to pain ; and (2) to obtain muscular relaxation, as in 

 breaking down adhesions (p. 274), in cases of difficult foaling, 

 and in the reduction of inguinal hernia (p. 287). 



ACTION. — ^There are three stages in the continued effect of 

 chloroform on the horse : (1) Nervous excitement, which will 

 be shown by struggling and frequently by neighing. During 

 this time the increased action of the heart is manifested by 

 violent throbbing of the carotid artery, the rapid pulsa- 

 tions of which can be seen in the jugular groove (p. 118). 

 (2) Insensibility. (3) Paralysis of the organs of breathing, 

 and finally paralysis of the heart. In giving chloroform for ordi- 

 nary surgical purposes, it is evident that we should not allow its 

 action to go beyond the second stage. The more quickly insensi- 

 bility is obtained, within of course safe limits, the less dangerous 

 will be the effect ; for if its production is induced by the prolonged 

 inhaling of even a comparatively small proportion of chloroform 

 in the respired air, the horse's system will get saturated with the 

 drug, and consequent danger of death will ensue from failure in 

 the action of the heart. As the horse bears the effect of chloro- 

 form extremely well, we should not be afraid to give it to him 

 in a fairly concentrated form. At the same time, we must re- 

 member that he requires air for breathing. Profiting by the 

 knowledge of the weakening effect which the prolonged administra- 

 tion of chloroform, even when well mixed with air, has on the 

 heart ; we should, as soon as the horse is rendered insensible, give 

 him only sufficient of the vapour to keep him under its influence 

 to the extent we require. In judging of the state of safety in 

 which the patient is when under the influence of chloroform, we 

 should be guided almost entirely by the condition of his breathing ; 

 for the action of the lungs in chloroform poisoning, ceases before 

 that of the heart. Stoppage of breathing and irregular breathing 

 are two symptoms of chloroform poisoning, the observation of 

 which should at once warn the operator to discontinue the ad- 

 ministration of the drug. Holding in the breath at first, will be 

 a sign that the chloroform is not sufficiently diluted with air. As 



