2 4 8 



character, and accompanied by a change of hosts, you 

 will realise the practically illimitable extent of the territory 

 that remains to be explored. And if, added to all this, 

 you contemplate the kind of occupation and sacrifices 

 demanded by researches of this order, you will, perhaps, 

 not be altogether surprised that so few scientists have 

 troubled themselves about the entozoa of the lower animals. 



Notwithstanding that so little has been done, sufficient 

 evidence can be brought forward to show ' that grave 

 injuries, and even death itself, result to "hosts" of every 

 degree ; but it does not follow that proofs, which to the 

 eye of the practised helminthologist are clear and con- 

 vincing, will have due weight with those who are new to 

 the subject. No person unfamiliar with the working of 

 parasites, and with the appearances presented on dissection, 

 is in any position to form a correct conclusion. The 

 scepticism which prevails respecting the role of parasites 

 in professional quarters is painful to the last degree. 



When recently at the Royal Society, Professor Huxley 

 communicated his instructive paper on Saprolegnia Jerax, I 

 felt tempted to rise and speak as to the parallelism which 

 subsists between the injurious action of external and 

 internal parasites relatively, whether animal or vegetable. 

 As I refrained on that occasion, I was the more gratified 

 by the opportunity recently afforded of incidentally calling 

 the attention of the Congress to this subject* Whilst 

 the fullest attention has been paid to the parasitic fungi, 

 little or no regard has been paid to the entozoa or internal 

 animal parasites. As a matter of fact all the Salmonidae 

 not to speak of other families are liable to be largely 

 invaded by entozoa, but it is hard to say to what extent 



* See Reports of the Conference on Fish Diseases given in Land 

 and Water for July 7, 1883, p. n. 



