39] 



CHAPTER XIX. 



Intbenal Parasites. 



general remarks sketch of the anatomy of the organs of 



digestion leeches bots tape worms-^worms. 



General Remarks. 



The "General Remarks on Parasites" made on p. 130 et seq., 

 apply equally well to the subjects of this chapter. It would have 

 been more correct though less convenient when writing in popular 

 language, for me to have put at the head of this chapter, " Non- 

 microbic Internal Parasites.'' Parasites may be divided into those 

 which are microbes (microscopic organisms), and those which we 

 may see with the naked eye, or with a magnifying glass of low 

 power. In the present chapter, I shall write solely about the 

 latter, and shall reserve for chapter XXII. any remarks I may have 

 to make about the former with reference to their capacity as pro- 

 ducers of infective diseases. Disease producing microbes belong, 

 as a rule, to the vegetable kingdom. 



The parasites which I shall consider in this chapter are those 

 of the more common kinds that invade the internal organs of the 

 horse. 



Sketch of the Anatomy of the Organs of 

 Digestion. 



THE DIGESTIVE APPARATUS of the horse, like that of man, consists 

 of the alimentary canal, in which the food is digested ; and various organs 

 which promote the digestion and transit of the contained food. 



THE ALIMENTARY OAJSTAL is formed of the mouth, pharynx, gullet, 

 stomach, small intestine, and large intestine. 



THE MOUTH consists of the lips, cheeks, tongue, hard palate, soft 

 palate and the surfaces in which the teeth are implanted (dental arches). 

 The lips help to take up solid and liquid food, and to retain it and also 

 saliva in the mouth. The cheeks, conjointly with the tongue, place the 



