126 PARASITES OF MAN 



opportunities of procuring water from localities where dogs 

 abound. In regard to water drinking, there is ground for 

 believing that the addition of a very little alcohol is sufficient 

 to destroy the six-hooked embryos of Tcenia echinococcus whilst 

 still in ovo ; and there is no doubt that water raised to a tem- 

 perature of 212 Fahr. will always ensure the destruction of the 

 larvae. Boiled water by itself is by no means palatable. The 

 reason why the upper classes comparatively seldom suffer from 

 hydatids may be attributed to the circumstance that those few 

 who drink water take the very proper precaution to see that it 

 is either " pump " or fresh spring water in which no living 

 six-hooked embryos are likely to exist. So far as hydatids are 

 concerned, wine and beer drinking is preferable to water- 

 drinking ; yet if water is carefully filtered no evil of the para- 

 sitic kind can possibly result from its imbibition. An ordinary 

 charcoal filter will effectually prevent the passage of the ova, 

 since their diameter is nearly 5 ^ of an inch. 



From what has been stated it follows that personal and 

 general cleanliness are eminently serviceable as preventions 

 against infection, but to ensure perfect success other precautions 

 must be exercised, especially in relation to our contact with 

 and management of dogs. Leuckart puts this very clearly when 

 he says : " In order to escape the dangers of infection, the 

 dog must be watched, not only within the house, but whilst he 

 is outside of it. He must not be allowed to visit either 

 slaughter-houses or knackeries, and care must be taken that 

 neither the offals nor hydatids found in such places are acces- 

 sible to him. In this matter the sanitary inspector has many 

 important duties to perform. The carelessness with which 

 these offals have hitherto been disposed of, or even purposely 

 given to the dog, must no longer be permitted if the welfare 

 of the digestive organs of mankind is to be considered. 

 What blessed results may follow from these precautions may 

 be readily gathered from the consideration of the fact that, 

 at the present time, almost the sixth part of all the inhabitants 

 annually dying in Iceland fall victims to the echinococcus 

 epidemic" (1. c., s. 654). Similar measures had previously 

 been recommended in less explicit terms by Kiichenmeister, 

 who in effect remarked that the principal thing was to ensure 

 the destruction of the echinococcus vesicles. He also recom- 

 mended the expulsion and annihilation of the Ta-rtia echinococcus. 

 In order to carry out this idea, it was suggested by Dr Leared 



