52 
HoGG^ on Parasitic Fungi. 
3d. Competent observers have not been able to find tliem 
in the diseases they are believed to engender. Thus Mal- 
herbe_, Cazenauve^ and Wilson deny the existence of a vege- 
table fungus in Porrigo scutulata (common ringworm), al- 
though this is described and depicted under the name of 
Tricophyton tonsurans by trustworthy observers. 
Cazenauve^ Didot^ and Wilson deny the existence of the 
Achorion Schoenleinii in Favus^ or cupped ringworm. Wilson 
and Cazenauve deny the existence of the Microsporon 
Audouini in Porrigo decalvans= In reference to the state- 
ment of the latter observer (Cazenauve) it must be borne in 
mind that he candidly acknowledges his ignorance of the 
microscope ; and not to make an unfair use of these nega- 
tive arguments, I must confess that I have seldom been dis- 
appointed in finding some kind of fungoid growth in all the 
diseases supposed to be produced by them; nevertheless, 
such is the similarity of form and growth in the specimens 
examined, that I have failed to make out an identity between 
the variety of parasite and the disease whose name it bears. 
Thus, in a case of Porrigo in a girl of sixteen, which had 
existed for nine years, from neglect and dirt, I found the 
fungus (fig. 11) described by Robin and Kiichenmeister as 
peculiar to Plica polonica, a disease almost unknown in this 
country. 
In the cases related of Tinea tarsi, I found sporules of the 
fungus described by Ardsten as the Puccinia favi. Robin 
also found in Favus the Puccinia occurring together with 
the Achorion Schoenleinii^ the latter presenting itself as a 
constituent of the cups or crusts, while the Puccinia occurs 
afterwards on the desquamation of the epidermis ; and this is 
thought by some to warrant the opinion that the Achorion 
is only the spermagonial form of the Puccinia favi. Again, 
it is broadly asserted by others, that the several morbid con- 
ditions are mutually convertible ; and that Lichen, Eczema, 
Impetigo, Psoriasis, Lepra, Mentagra, &c., are but modifica- 
tions of one and the same disease, resulting from accidental 
conditions, and not always found perfectly distinct ; nay, so 
often are they combined and complicated, that dermato- 
logists have assigned special names indicative of their mixed 
character, such as Eczema impetiginodes. Eczema leproides, 
Lichen urticatus. Erythema papulatum, &c. 
It may be said that most of the cases examined by Mr. 
Hunt and myself should be referred to the latter forms of 
disease, and that the finding of parasitic fungi might have 
been a priori expected; in short, ought to have been found 
by us : but keeping in view this contingency, Mr. Hunt 
