126 
Herpetomonas and Cnthidia 
complete cessation of nuclear division. In this case we not only find 
hypertrophy of the nuclear apparatus, but also premature division 
unaccompanied by hyperproduction of volutin. So an antagonistic 
relation seems to exist between the power of nuclear division and the 
hyperproduction of volutin, which is in accordance with Hertwig’s 
observations on Actinospliaerium. 
We note a remarkable analogy between the degenerative appear¬ 
ances of the above mentioned flagellates and of Actinospliaerium, but 
here I think the analogy ends, for it is impossible to consider the 
degeneration of Trypanosoma and Herpetomonas as “ physiological,” 
i.e. as a necessary consequence of vital functions, only to be avoided by 
copulation or encystment. It is true that in the case of Herpetomonas 
encystment occurs; it is even accompanied by elimination of chromatic 
substance from the blepharoplast; but even here no degeneration 
occurs unless unfavourable trophic conditions occur (honey, fruit-juice, 
provoking the development of yeast cells and bacteria, which produce 
toxic substances). 
Trypanosomes remain apparently healthy for an unlimited number 
of generations; the degenerative phenomena already described occur 
only when distinct toxic influences (death of the host, drug treatment, 
etc.) come into action. It is true that cyclical depressions and revivals 
have been described recently in Trypanosoma gambiense (Ross and 
Thomson, 1911) and Fantham (1911) has shown that these depressions 
coincide with the production of resistant forms; but according to Ross 
and Thomson these depressions occur under the influence of protecting 
reactions from the body of the host. The degeneration of Piroplasma 
canis is also due to toxic effects. So we see that in all these cases the 
degeneration is not “ physiological ” but directly due to external noxious 
influences. If these influences are checked no such degeneration takes 
place. 
One may ask whether this is a special condition of these parasites 
or whether the “ physiological ” degeneration of Hertwig actually exists. 
I cannot answer this question, but the researches referred to suggest 
the possibility that “ physiological ” degeneration of Actinospliaerium 
and “depression” in cultures of infusoria, as observed by Calkins (1909), 
are due to toxic substances produced in these cultures and are not 
a consequence of the vital functions, eo ipso. Similar doubts have been 
recently expressed by Borowsky (1910). 
