11? DISEASES OF ANIMALS. 



BOTS. 



The horsefly, or bot-fly, (^Oestrus equi,) appears it 

 July, and continues till cool nights in the fall; she lays 

 her egg on those parts of the horse liable to be licked by 

 his tongue, on which he takes the eggs, and they soon 

 find their way to the stomach, where they are hatched ; 

 or they hatch on the horse, and may be passed into the 

 stomach. 



The young bots adhere to the stomach by little hooks, 

 and are nourished by the mucus of the stomach, or the 

 food it contains, until the next spring, or first of the 

 summer, when, having attained full size in the larvae 

 state, they drop their hold, and are carried along with 

 the contents of the stomach, and voided. They then 

 burrow in the ground, and remain a few weeks in the 

 chrysalis state, when they undergo a more important 

 translormalion, and become flies, or perfect insects, 

 pursuing the course of their predecessors. 



This is the course that nature has provided for their 

 propagation ; and some persons contend tliat bots never 

 injure a horse, but are beneflcial. Others contend that 

 they never injure a healthy horse ; but when a horse is 

 iliseased, they are deprived of their usual food, and then 

 they may seize upon the stomach, with a view of clear- 

 ing out for better quarters. 



Bots have sometimes collected in large numbers, and 

 stopped up the passages to and from the stomach, and 

 have thus occasioned death. 



Numerous remedies have been recommended for the 

 destruction of bots, which are said to be sure ; and yet 

 it is contended that any medicine sufficiently powerful 

 to kill them would kill the horse also; for bots have 

 lived in rum, twenty-five hours ; in a decoction of 

 tobacco, eleven hours ; in strong elixir or vitriol, two 

 hours ; in spirits of turpentine, forty-five minutes ; in 

 fish oil, linseed oil, and brine, ten hours, without any 

 efiect. IMore powerful substances would kill the horse. 



Yet certain maiicines may disgust and nauseate the 

 bots, and others iiay be ilatable, and serve to quiel 



