35 



fodder during mastication. It has Lecii calculated tliat out of the raany hundreds 

 of eggs deposited ou a single horse scarcely one out of iifty of the larvse arrive within 

 the Stomach. Notwithstanding this waste the interior of the stomach may become 

 completely covered (cuticular portion) with bots. Whether there he few or many 

 they are anchored in this situation chiefly hy means of two large cephalic hooks. 

 After the hots have attained perfect growth thej voluntarily loosen their hold aud 

 allow themselves to he carried along the alimentary canal until they escape with the 

 feces. In all cases they sooner or later fall to the ground and when transferred to 

 the soil they hury themselves beneath the surface in order to undergo transformation 

 into the pupa condition. Having remained in the earth for a period of six or seven 

 weeks they finally emerge from their pupal-cocoons as perfect dipterous (winged) 

 insects— the gad-fly. It thus appears that bots ordinarily pass about eight months 

 of their lifetime in the digestive organs of the horse. 



The species just described infest chiefly the stomach and duodenum- 

 small gut leading from the stomach. 



Another species of oestrus affecting the horse is the oestrus hoemorrhoi- 

 Aalis. These are found fastened to the mucous membrane of the rectum, 

 (last gut) or even outside upon the anus, and occasion much irritation 

 aud annoyance, and, at times, require to be removed by the fingers or 

 forceps. 



The opinion, almost uni'rersally entertained, that bots frequently 

 cause colicky pains, is erroneous. Itis very common to hear by-stauders 

 declare that almost every horse with abdominal pains "has the bots," 

 and their suggested treatment is always varied and heroic. 



Almost all horses in the country, as well as horses in the cities during 

 their first year there, have " the bots." It is in exceptionally rare in- 

 stances that they produce any appreciable symptoms or disturbances. 

 In my own practice I have never known bots to be the cause of any 

 serious ailment of the horse ; and only once has my father, in a practice 

 extending over fifty years, known bots to be the cause of death. In 

 this instance the bots seemed to have simultaneously loosened their 

 hold upon the mucous lining of the stomach, and were forced as an im- 

 permeable wedge into the pyloric orifice, or outlet, of the stomach, and 

 thus, preventing the passage of food or medicine, produced death. 

 Were the bots to attempt to fasten themselves to the sensitive lining of 

 the bowels in their outward passage they might cause irritation and 

 expressions of pain in the form of colicky symptoms, but this they sel- 

 dom or never do. The opinion frequently expressed ixt postmortem ex- 

 aminations, when the stomach is found to be ruptured, that " the bots 

 have eaten through the stomach," is again a mistake. Bots never do 

 iMs; the rupture is due to overdistention of the viscus with food or 

 gases. Some writers on veterinary medicine have even urged that bots, 

 by their presence, stimulated the stomach secretions, and were thus 

 actually an aid to digestion. This opinion is as far from the truth as 

 the more general one referred to above, concerning the harm they do. 



Bots may, and probably do, when in large enough numbers to be 

 fastened to the true digestive portion of the stomach, slightly interfere 

 with digestion ; the animal may not thrive, the coat stares, and emacia- 



