154 
Being at present fully occupied with sonic other work I must 
limit myself to the discussion of some points of primary iniportance, 
but it is possible that I may take an early opportunity of returning 
to the subject in more detail. Speaking quite generally, I may say 
even now that those of us who have seen anything of Bilharziosis b 
Egypt are convinced that the scientific problem it offers is mwe 
complicated than Dr. Sa.MBON seems to imagine; it is a problem 
which will require a long and close collaboration of the Anatomist 
the Pathologist, and the Helminthologist before it may be considered 
as solved in every detail. There is, further, one thing which can not 
be too strongly emphasised at the very outset, and this is that any 
theory, be it ever so cleverly based on the biology of the parasite, 
must be wrong if it contradicts the facts supplied by the Anatomist 
and the Pathologist; and also that any other theory, however 
plausible its explanation of the anatorao-palhological observations, 
can not represent the truth so long as it is irreconcilable in any detail 
with the biology of the parasite. I may mention in passing that 
several theories recently brought forward as explanations of the 
aetiology of certain huniaii diseases caused by worms are open to the 
latter objection; the theory of Sambon is the latest of these, and a 
very interesting one it is, not perhaps so mucli for the arguments by 
which, but on account of the manner in which it is supported. 
In order to make the purport of what I have to say hereafter 
quite clear, I will state that I do not consider it my task to prove 
whether or no there exists a Schistosomum viansoni. 
scientific workers it is a good custom that anyone who believes he 
has made a new discovery also takes the trouble to prove it ; it 
not customary among scientists to assert something and call for the 
help of others to establish it. In the case which I am about to discuss, 
it is Dr. Sambon who, acting ujjon a suggestion of Sir Patrick 
Manson, formally ]5ublished Schistosomuin mansoni as a new spedes^ 
After the usage generally adopted in science, the merit of the 
discovery is his when the discovery is right. But with him also must 
rest the responsibility of bringing forward all the evidence which may 
be reasonably demanded in support of it. Dr. SAMBON, indeed, 
supports his action by a certain amount of evidence; but he 
IS o vious y aware himself that, especially, its zoological pad 
O-e. t e possibility of distinguishing the adult forms) is 
