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tation by which important chemical products are obtained; and 
they change dead matter (so called) into the state best fitted for the 
support of future generations. They may also live at the expense 
of the living tissues of plants and animals, although possibly only 
upon those which are depressed by some cause below a full vital 
energy. The muscadine of the silk worm and the oidium of the 
Madeira vineyards are cited as examples of the importance of such 
destructive agency. 
The effects of such fungi upon the surface of men are never fatal, 
or constitutionally hurtful, but they are greatly annoying and may 
last for many years. Schcenlein in 1839 first recognized the cryp- 
togamic character of the.crusts of Favus; and after much dispute, 
the following affections are now safely referred to similar causes— 
- Ringworm (in which the author includes as varieties Bezemé 
marginatum, Tinea tonsurans, Sycosis, and Ringworm of the Nail) 
and Pityriasis versicolor. Still a subject of dispute is Alopecia 
areata, and Myringomycosis, both of which are often accompanied 
if not caused by cryptogamic growths. On the other hand the 
chignon-fungus and some other controverted cases are safely con- 
sidered pseudo-parasites, ; 
Several of these parasitic plants are common upon the domestic 
animals, and in some instances may possibly have been originally 
derived from them. 2 aia 
On the question of the identity of the several vegetable pal 
asites, and their relations to the common moulds, much study 
s been expended, and with remarkably contradictory Tes 3 
Equally safe observers reach the extreme opposite conclusions. 
The methods of investigation are clinical observation, eee 
inoculation, and development of the fungi by cultivation- ; 5 
ically favus is distinct, and the others are separable with reason 
standing the deceptive inferences which may easily pre 
accidental coincidences : and cultivation, while it usually fu 
an abundance of penicillium, aspergillus and other fa 
is so liable to error from their accidental introducti 
as yet, in the author’s judgment, furnished no suffici a a 
admitting the identity of the subjects of the paper with ae Be 
common moulds. tions 
The vegetable parasites are an occasional cause of al ‘They 
of the epidermis and its appendages, causing baldness, eT 
