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contribution is tbat of Katsurada and Hashegawa, already referred to, 
on the mode of infection. Another question of some moment is the 
possibility of the existence of a second species of Schistosomum in 
Egypt and of yet another in South America, both differing from the 
ordinary form in the possession of lateral-spined eggs. Sambon (1909) 
and Da Silva (1908 and 1909) have supported this contention, but it 
has been strenuously opposed by Looss (1911) who maintains that one 
and the same species produces both varieties of eggs and that the 
variations have their origin in the egg-producing apparatus. As far 
as can be judged, Looss’ view appears to be the more probable one. 
Probably no parasitic disease, other than malaria, has aroused such 
widespread interest or has called forth such a mass of literature as 
hook-worm disease (Ankylostomiasis). It was a remarkable discovery, 
indeed, that the greater bulk of the very numerous cases of tropical 
anaemia was due to the infection with the hook-worm. The worm 
itself was discovered about 70 years ago, but little was known regarding 
it for 40 years, and it was not until 15 years ago, when Looss started to 
deal with the subject, that the material points in the life-history began 
to be known. Reference has already been made to Looss’ conclusive 
monograph which summarises practically all our present knowledge on 
the subject from the biological side. It is impossible to discuss here 
the numerous medical contributions which have been made regarding 
treatment, prophylaxis, and so forth, but reference must be made to the 
Milroy Lectures (1911) by Boycott, who, in association with Haldane, 
did much good work in studying the disease as it occurred in this 
country in the Cornish tin mines. 
Hydatid disease, again, has furnished the subject of much investiga¬ 
tion. Occurring as it does, not only in man, but also in many of the 
domesticated animals it has been dealt with extensively both by medical 
men and by veterinarians. In Germany it has formed a favourite subject 
for Theses and Dissertations, the most considerable of which is that by 
Becker (1907). The most noteworthy results have been achieved in two 
directions, first by Deve (1907-1912) who has studied the experimental 
production of hydatids, and secondly by Weinberg and numerous others 
who have been concerned with a means of diagnosing the presence of 
the disease, which is an extremely difficult matter by ordinary clinical 
methods. To Weinberg undoubtedly belongs the chief credit of utilising 
a method of diagnosis which gives promise of being a reliable and useful 
aid to medicine, namely, the serological method. Serum-diagnosis is 
one of the most recent of medical methods and has been found of great 
