Paek. — On Animal and Vegetable Parasites. 453 



culosis " of Metchnikoff. It is also very clearly seen in the 

 lungs of sheep and in the intestines as small knobs. When 

 we find a large number of encysted parasites of this kind it is 

 easy to see how readily one can mistake such cases for tuber- 

 culosis, especially when no microscopic examination is made, 

 as in sheep they cannot be seen without a lens of some kind. 



Cancer is the next subject to command attention. This is 

 ■said to be due to the consumption of animal food affected with 

 cancer. For my own part, I have no proof of this, but I can 

 show you specimens of the latest form of cancer-parasites in 

 man, and also certain intracellular bodies in cattle that bear 

 a striking resemblance to those bodies as described by Buffer, 

 Walker, Fox, and others ; but, until we have proof of the 

 statements made concerning cancerous meat, I would say, 

 keep a contented mind until proof is obtained. 



In order to prove what I have said, we will now examine 

 the preparations, under the microscopes, of cancer, actinomy- 

 cosis, tuberculosis, Spiroptera reticulata, and also a prepara- 

 tion by Dr. Whittell, of Adelaide, of actinomycosis and 

 Spiroptera reticulata in the same tumour, giving further 

 proof of another vegetable parasite finding a nidus in the 

 same tumour. 



5, York Terrace, Regent's Park, N.W., London, 

 Deab Mr. Park, — 8th December, 1893. 



I was very glad to hear from you again, and to have an account 

 of your extremely interesting observations. I am also greatly obliged to 

 you for the thirteen beautiful sections you have sent me, which I have 

 examined witli the greatest interest. 



There is not a doubt that these preparations represent sections 

 through some kind of new growth, which form cysts containing in their 

 interior a peculiar-looking worm, which resembles marvellously and is 

 probably identical with the Spiroptera reticulata. 



In some of tlie sections one could also see large giant cells, vyhich 

 were evidently tilled with all kinds of debris, which were probably bits of 

 embryos, or even of adult worms, which these giant cells had taken into 

 their interior, killed, and digested. The worms varied to a great extent, 

 and, in some, one could see the process of the formatioa of embryos, &c. 



I was greatly interested also in some of the sections which showed 

 the Spiroptera as well as the tubercle bacilli at the periphery. 



I must say tiiat tliis discovery of yours strikes me as being entirely 

 new, and one which might prove useful in elucidating various pathological 

 problems. 



It strikes me as exceedingly probable that the Spiroptera penetrates 

 first, and then, through the irritation which it produces, and through its 

 altering of tlie animal's resistance, it gives the tubercle bacillus a chance 

 to invade the body and thrive : but I do hope that you and your assistants 

 will work out this most interesting problem. 



I was also greatly interested in tlie notes of cattle slaughtered by 

 you during the year 1893 in Queensland. There can be no doubt from your 

 list that true tubercle must be exceedingly rare, and that actinomycosis 

 and diseases due to worms, Spiroptera, &c., must be equally common. I 

 confess I should have been greatly astonished had tubercle been as fre- 



