288 DISEASES OF THE STOMACH, 



contact with, the lining membrane of the stomach, and^ 

 consequently, not conveniently placed for such imbibition : 

 in fact, their mouths must be, I should imagine, enveloped 

 and concealed by mucus, since abundance of that food is 

 deposited upon the surface of the alimentary mass, to sheathe 

 the stomach from mechanical irritation. And, for my own 

 part, I feel inclined to think that this mucus constitutes 

 their food ; and this is aliment, probably, which possesses 

 little or no excrementitious matter, since it is itself re- 

 absorbed in many parts of the body ; and what favours this 

 opinion is, that there are bots within the sinuses of the head, 

 in the skin, &c. of cattle, which can have no other suste- 

 nance save the secretions of those parts, a fact that Mr. Clark 

 himself admits ; also that worms in the intestines of animals 

 are nourished in the same way, is rendered highly probable 

 by the existence of the ascaris within the colon and rectum — 

 cavities which contain little or nothing else but what is 

 excrementitious. 



About the month of June or July it is that bots, having 

 quitted the stomach and been transported with the aliment 

 through the windings of the intestinal tube, become dis- 

 charged in the fseces ; also at this period it is that people 

 discover, for the first time, that their horses (particularly 

 those that have been at grass the preceding autumn) have 

 nvhat they call " worms ',^' to get rid of which vermifuges all 

 at once come into pressing requisition. If, however, these 

 well-meaning people will have but a little patience, their 

 imaginary plagues will soon quit the bowels of their horses 

 of their own accord : the time being now arrived for them 

 to assume other forms, and so answer the remaining ends 

 of their nature. The larva^ being ejected, lies not long ex- 

 posed upon the ground, or concealed in dung, but quickly 

 dries up and sinks into the state of chrysalis or grub, in 

 which torpid condition it continues for a few weeks. At 

 the expiration of this time, " the superfluous moisture being 

 removed, and the parts of the future insect being hardened 

 by drying, it bursts from its confinement, and the fly appears 

 making its exit at the small end." — " On quitting their 



