70 
chanical disturbance produced by their presence in the human body, but the toxin, 
which produces illness, and may cause death, (Translation.) 
Yaullegeard (1901) states that the products soluble in water obtained 
b}" him from a number of different cestodes contain two sorts of sub- 
stances, one soluble in alcohol and the other precipitated by it. While 
no experiments were made with II. iiana^ in the case of Bothrlocejyh- 
alus piuictatus he was able to demonstrate that the substance soluble 
in alcohol contained an alkaloid very similar to curarin, while in the 
substance precipitated by alcohol there was a sort of toxin-ferment 
which acted upon the nervous centers and disorganized the relations 
of the nerve cells. In his conclusions he says: 
In studying the products contained in different species of worms, we have isolated 
two toxic substances, one of which acts upon the nervous centers, while the other acts 
upon the muscles. AVe are therefore justified in suspecting the importance of these 
factors in verminous maladies. The critical study of this subject has brought to our 
attention a large number of symptoms analogous to those provoked by the injection 
of the toxic substances. * * * Our chemical theory, deduced from our experi- 
ments, permits us to understand how good health is possible in spite of the presence 
of worms. This result should occur whenever the excretion eliminates a quantity 
[of the toxic materials] equal to the absorption, for in this case the dose contained 
in the organism is not sufficiently active. The troubles correspond to the accumula- 
tion of toxic products; one readily comprehends that when some morbid influence 
becomes effective, it may determine the apj>earance of symptoms due to worms, which 
had been present for a long time without manifesting themselves. (Translation. ) 
In the case of 7/. nana it seems probable that the elimination of toxic 
materials Avhich are absorbed b}" the host is one of the most important 
factors in the etiology of symptoms. Upon this point Linstow (1896b, 
pp. 190-191), after reviewing shorth" the symptoms which have been 
attributed to the parasite, remarks: 
That such a minutely small, delicate animal can not produce these serious disturb- 
ances through mechanical irritation, perhaps does not need the proof that its virulence 
must be very intense. (Translation.) 
The analysis of the symptoms reported in the various cases of 
llymenolepis nana is complicated by a number of circumstances. 
Among others, the question arises as to whether the phenomena 
exhibited were due to helminthiasis, or to other causes; this question 
is more or less delinitely decided in some instances by the effect of 
anthelmintic treatment. Again, in those cases in which there was a 
multiple infection, to what extent did Ili/msnolepis nana inffuence 
the symptoms and how much are the other parasites to be blamed? 
This is a question which can not be answered with certaint}", but if the 
other parasites are comparatively few in number, as manifested by the 
number of eggs in the feces or by the number of worms passed after 
treatment, and are of kinds which do not usualh^ cause much trouble, 
or if the s^miptoms disappear and recur after successive treatments in 
correspondence with the recurrence in the feces of the eggs of II. nana^ 
we may assume that it is by the latter j^arasite that the symptoms are 
chiefly determined. 
