1885.] the Dog bred from the Echinococci of Man. 



451 



In all these cases, however, the dogs were fed with Echinococci 

 obtained from the lower animals (Echinococcus veterinorum). As 

 many able zoologists believed that there were two or more species of 

 Echinococcus, it became a matter of considerable scientific interest, 

 and indeed of great practical hygienic importance, to determine 

 whether this really were so or not. 



Both Kiichenmeister and Zenker endeavoured to breed the adult 

 tapeworm from Echinococci derived from man, but without success. 



In 1863, however, Krabbe and Finsen in Iceland, as well as Naunyn 

 at Berlin, succeeded in breeding Taenia echinococcus from the hydatids 

 of man, but for reasons to be mentioned hereafter, their experiments 

 can scarcely be regarded as decisive. 



In order that experiments of this kind may be considered as satis- 

 factory, certain conditions must be fulfilled. It is necessary — 



1. To employ animals which could not be suspected of having been 

 infected prior to the time of experiment, or to take steps to remove 

 any entozoa that might be present, by the previous administration of 

 suitable vermifuges. 



2. To place the animals under circumstances in which it wouid be 

 impossible for them to acquire infection from any accidental source. 



3. To feed them with the living Echinococci of man. 



4. To ensure complete success it is necessary not only that the 

 tapeworm should be found in the intestine of the dog, but also that 

 it should be found in numbers proportionate to the number of Echino- 

 coccus heads administered, and, moreover, the stage of development 

 reached by the tapeworms should correspond with the date of the 

 experimental " feeding." 



5. No kinds of tapeworms should be present excepting such as can 

 be satisfactorily accounted for. 



Judged by this standard, neither the experiments of Krabbe nor 

 those of Naunyn can be regarded as decisive. 



Six separate experiments were performed by Krabbe* and Finsen, 

 the number of dogs employed being nine. 



Experiments Nos. 2, 3, and 5 were entirely unsuccessful, no speci- 

 men of Taenia echinococcus being found in the dogs. These experi- 

 ments included four out of the total number of nine dogs observed. 



Experiment No. 1. — In the autumn of 1862 M. Finsen sent to M. 

 Krabbe a glass containing Taeniae found by him in the intestines of a 

 young dog, to which some months previously he had administered 

 Echinococci obtained from a patient operated on by Recamier's 

 method. 



These Taeniae were chiefly specimens of Taenia cucumerina, but there 

 was found also one mature joint of Taenia echinococcus. 



* "Recherches Helminthologique9 en Danemark et en Islaude," par IT. Krabbe, 

 Copenhagen, 1866, p. 49, et seq. 



VOL. XXXVIII. 2 K 



