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A Cause of Appendicitis 
bacilli at the points where the suckers of the tapeworms were attached 
to the intestinal wall. Weinberg concludes this part of his thesis by 
saying that his microscopic sections show that: 
(i) The tapeworm by fixing itself on the intestinal mucosa, sets 
up an intense congestion at the point of fixation. 
(ii) At the same time it applies to this point of the intestinal 
mucosa such bacteria as are to be found on its suckers, and on the 
other hand it imprisons, between its suckers and the intestinal wall, 
such bacteria as existed before on this portion of the mucosa. 
(iii) A considerable number of leucocytes make their way to the 
surface of the mucosa and take up the bacteria. 
(iv) At other times, the bacteria penetrate into the thickness of 
the mucosa and set up inflammatory changes which may end in one of 
those ulcerations which are often found at the point of fixation of the 
tapeworm. 
It seems then that Weinberg does not allow that the Cestode head 
breaks the continuity of the mucosa. He does not give precise details 
as to the species of “ tenia ” he is dealing with and it may very well be 
that the unarmed species do not penetrate the lining of the intestinal 
wall. But whoever will study Piana’s Paper will I think have little 
doubt that in such genera of tapeworm as Davainea, and I think we 
may add Hymenolepis, there is a solution of the continuity of the 
lining mucosa of the host. 
We must also not leave out of account the fact that some people 
and races are much more “ tolerant ” of all sorts of parasites, bacterial 
and others, and when infected suffer far less than do others who are 
susceptible to their action. 
I am not quite sure how much injury to the mucosa is required 
to admit germs which are harmless within the gut lumen, but patho¬ 
genic when they gain free access to the blood or tissues, especially when 
the latter have been injured. 
Without doubt the passage of the bacteria which set up intestinal 
disease is immensely aided by any agent which causes a lesion in the 
mucosa. Such lesions are normally caused in man—apart from any 
irritating substances he may swallow with his food, such for instance 
as the powdered diamond or glass which is said to have been used in 
Italy in the palmy days of poisoning—by entozoa. 
I have in this paper confined my attention in the main to but three 
human intestinal parasites, all of them nematodes. There are, however. 
