OF PARASITIC ORIGIN. 35 
view of the alleged distinction. But though his view is 
true as far as the parasite is concerned, how different it is 
for the patient on whom it grows, whether the fungus is luxu- 
riating absolutely on his tissues, or merely on some effused 
morbid product, on which it grows as it might on any other 
decayed matter. As Dr. Fox well shows, the growth of the 
fungi which cause tinea requires the existenee of a peculiar 
soil, which depends on a particular diathesis and condition of 
blood ; whereas it is evident that such fungi as the forms 
called Leptomitus, Mucor, Bennett’s lung fungus, Leptothrix, 
Cryptococcus, and perhaps Sarcina, require no such blood-con- 
dition; but, with Tricophyton ulcerum and Puccinia, are to 
be considered as merely accidental phenomena growing on 
soil external to the human body and foreign to it, such as 
dried pus or mucus, decaying food, acid fluids, and the like; 
they cause no lesion, and are not parasites on the human body 
in the true sense of the word. 
Dr. Fox’s view on the vexed question of Sarcina ventricult 
is that it is never a cause of disease (7 e. it may be called a 
false parasite). He adduces a good deal of evidence on his 
side, but the question cannot yet be considered as settled. 
The writer has seen two cases of continual vomiting during 
life of a fluid full of Sarciniz, and no lesion could be detected 
after death. (A case in point is also recorded in the ‘ British 
Medical Journal’ for February 5th, 1859.) 
But the real value of the treatise under review is in the 
record of the results which the author has arrived at by expe- 
riments and observations on the relations subsisting between 
the various so-called species of parasitic fungi, both Epiphytes 
and Entophytes. These results are contained in the second 
part of the work,and may be summed up thus :—Starting with 
the proposition, which he proves, that there is no such thing 
as spontaneous generation of fungi, and that the same fungi 
may exist in various forms under different conditions of soil, 
medium, and the like, Dr. Fox shows conclusively how in- 
adequate are the published descriptions of the parasites to 
distinguish one from another, and how they assume one 
another’s forms. He remarks that there is “no want of 
descriptions of the various parasites found; but when the 
attempt is made to apply them practically, many will indicate 
as well one as another fungus” (p. 115). Moreover, he 
demonstrates that the distimctions of the different kinds of 
tinez are those of degree, not of kind; and he firmly declares 
that the fungus which produces them is one and the same, 
merely modified in appearance by its seat and the soil, the 
