292 DR. T. S. COBBOLD ON ENTOZOA IN THE DOG. 



surgeon. The adult parasite has frequently been reared by foreign 

 experimenters ; but although several hydatid-feedings have been 

 administered to dogs in England, only one such feeding has, so 

 far as is known, been attended with positive results. This in- 

 stance has recently been communicated to the Royal Society, the 

 experiment having been made by Mr. Edward Nettleship*. I 

 am sorry to believe also that I may have previously reared this 

 parasite. I say " sorry," because the subject of the experiment, 

 a small black dog, was liberated, by an ill-designing person, a 

 few hours before the time I had appointed for destroying 

 it. It is true that I had previously, in one or two other dogs, 

 obtained only negative results ; but in those instances none of 

 the conditions likely to ensure success were so favoi\rable as in 

 the case of the liberated animal. At all events, Mr. Nettleship, 

 following up the experiment after a precisely similar method to 

 that I had adopted, obtained a complete success. The freedom of 

 one animal harbouring Taenia echinococcus must be fraught with 

 serious danger to the community ; and yet it is to be feared that 

 at the present time several dogs thus infested roam at large in 

 this country. Certainly I have no desire to add to their number. 

 In Copenhagen Dr. Krabbe encountered this parasite in tioo only 

 out of 500 dogs ; and yet the parasite is probably more abundant 

 in Denmark than in England. In Iceland, on the other hand, 

 where the mortality from the hydatid- or echinococcus-disease 

 embraces one-sixth of all who die in that country. Dr. Kjabbe 

 found 28 dogs out of 100 harbouring this entozoon. Up to the 

 present time no person, I believe, in England has seen this para- 

 site in any dog which had not previously been made the subject 

 of experiment. 



In order to obtain an approximately correct notion as to the 

 amount of echinococcus-disease prevalent amongst us, I devoted 

 some three or four weeks in the winter of 1864 to an examination 

 of the collections of entozoa contained in nine of the principal 

 Pathological Museums of the metropolis. The results of this 

 search, independently of data derived from other sources of evi- 

 dence, have convinced me that hydatids are far more prevalent than 

 is generally imagined. In these collections I found no less than 

 195 instances of hydatid-disease out of a total of 368 cases of 

 helminthiasis of all kinds. It is my deliberate belief that not 

 less than 400 deaths annually occur in England from this source. 

 Doubtless, if one could acquire correct statistical evidence re- 

 ' Proceedings,' vol. xt. No. 86, p. 224. 



