160 
Development of Hook-worms 
upon the part of the householder, but to insure that these provisions 
are stringently carried out would involve a large amount of unremitting 
labour on the part of the sanitary officers. This labour could be reduced 
to a minimum by the intelligent co-operation of the general public. 
The insistence on the danger of defaecating elsewhere than in properly 
appointed places and of walking barefooted on wet ground or in pools 
of water would deter some persons from spreading infection and others 
from incurring it. 
To sum up, the chief hope of eradicating and preventing hook-worm 
disease lies in thorough sanitary measures, rigorously administered. 
The use of disinfectants. 
It has been a not infrequent question, put by public health bodies 
and by others interested in the matter, whether disinfectants or other 
substances could be employed to check the spread of Ankylostomiasis. 
This question appears of some importance but it loses much of its weight 
in view of what has been said above as to the simple measures necessary 
for the purpose. In spite of that it must be admitted that it would 
be valuable to have at our command some secondary and auxiliary 
measures. 
The use of ordinary disinfectants has most naturally been sug¬ 
gested, and a considerable amount of experimental work has been 
done on this matter. The results have shown that while fairly 
weak solutions of disinfectants such as izal or corrosive sublimate 
will kill the young larvae within a few hours, yet the eggs and fully 
grown larvae are much more resistant. These results, however, are 
based chiefly on laboratory experiments in which the disinfectant 
solutions have been kept in continuous and intimate contact with the 
infected material, and they are not altogether applicable to natural 
conditions. Under the latter conditions, e.g. in the case of a faecal 
deposit, the disinfectant would percolate through and drain away 
from the infected material in a very short time and so the effect 
would, to a large extent, be lost. Even in a closed receptacle only 
that part of the faeces in touch with the disinfectant would be 
immediately affected, although in the course of a week or a fortnight 
most of the larvae from above would find their way into the fluid and 
eventually be destroyed. For the purpose of preventing the spread of 
hook-worms it is unnecessary to add disinfectants to a properly con¬ 
structed sanitary pail, though of course their use for . other reasons is 
