PREFACE. 



Without any customary apology, either to the general public or to the members 

 of the medical profession, I introduce this elementary treatise. 



On all hands it is conceded that the subject of Entozoology has an important 

 bearing on questions affecting the maintenance of public health ; and it is to be 

 regarded as a matter of congratulation that the political economist of the present 

 day not unfrequently avails himself of the labours of the scientific naturalist. 



Since the publication of Mr. Rhind's snaall volume on the internal parasites of 

 the human body, so far back as the year 1829, I am not aware that any complete 

 work of a similar kind has been written by any English author. It is true that 

 we are in possession of several original and extremely valuable memoirs which 

 will bear advantageous comparison with the more numerous hrochures Issued in 

 foreign lands ; but, as regards works designed to embrace the study of Hel- 

 minthology, in its entirety, no such project has hitherto been attempted. The 

 void, however, has been more or less completely occupied by several able transla- 

 tions. First and foremost among these is the Sydenham Society's edition of 

 Kiichenmeister's standard work on the "Animal and Vegetable Parasites of the 

 Human Body," by Dr. Lankester, F.R.S. Secondly, we are presented with a 

 tolerably comprehensive outline both of the external and internal parasites of 

 man, in Mr. Huhne's edition of Moquin-Tandon's useful little book, entitled 

 Elements de Zoologie Mtdicale. Thirdly, we are furnished with an excellent 

 account of the general organization of the Helminths and Turbellarians in the 

 fifth and sixth sections of Dr. Burnett's American edition of Von Siebold and 

 Stannins' Lehrhucli der verf/leichenden Anatomie ; and, fourthly, there is Dr. W. A. 

 Smith's recently issued volume "On Human Entozoa," which is, for the most 

 part, an agreeable and practical excerpt from Davaine's remarkable Traite des 



