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10
Nevertheless, these forms are so wide-spread, that a great number
of the spores of these moulds undoubtedly reach the digestive
apparatus daily. As the discrimination, which allows some species
to pass the alimentary canal alive while others are killed, must
take place within the body, we have to consider for a moment the
discriminating factors which influence the fungous spore while on
its passage through the body of warm-blooded animals. Three such
factors present themselves: temperature, the action of gastric and
intestinal juices, the combined action of temperature and gastro-
intestinal juices.
The relation to temperature of the fungi isolated from the alimen-
tary tract of man and warm-blooded animals has alredy been dis-
cussed. They all grow vigorously at 37° C., that is, at blood-tem-
perature. Any. inhibitory effects of the body-temperature on these
forms are, therefore, out of question, and only the relation to blood-
temperature of forms with a lower optimum temperature than 37°
C., becomes of interest to us in this connection.
Most of the species of Aspergillus and Penicillium, indeed, all of
those forms which one would expect to find in the faeces, have an
optimum temperature considerably lower than 37° C. Aspergillus
glaucus is greatly retarded in its growth at 37° C. (WEHMER
67). Penicillium commune, P. roqueforti and P. camemberti do not
show any growth at all at this temperature (THom 63). Only
relatively few, however, are actually killed at 37° C.. Among these
are P italicum and P. digitatum (THom 63, WESTLING 70). Asa
rule the vitality of the spores of the green species of Penicillium is
not destroyed by being exposed to a temperature of 37° C. for a
shorter time. Spores of Penicillium frequentans, isolated from frog
and incubated for 48 hours at 37° C., invariably germinated when
brought into room temperature. CAMURRI (4) found that the ger-
minalion power of »P. glaucum» was set back when kept at 37°
C., but completely destroyed by prolonged exposure of the spores
to this temperature. TIRABOSCHI (65) found that spores of »P: glau-
cum», incubated at 37° C. first lost their vitality after 15 days.
Only very few germinated after having been incubated a month,
and these were delayed a couple of days in their germination.
The evidence on this point is conclusive and shows that the
temperature alone cannot be the decisive factor that brings about
the destruction of fungous spores during their short detention in
the alimentary canal. Even if growth is suspended or the germi-
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