ANALYSIS OF CONTINENTAL JOURNALS. 
845 
as the Milan fly, which is conveniently covered, and allowed to 
remain for twenty-four or thirty-six hours. When the blister 
is removed, the epidermis is found to be raised by a small 
quantity of serum ; this epidermis is detached, and on the 
humid surface is sprinkled a little of the favus dust, either in 
a dry state, or, which is better, damped by a drop of water. 
The surface thus sown may be afterwards covered by diachy- 
lon plaster — -a precaution which is not indispensable, but 
useful, as it maintains the surface in a state of humidity 
favorable to the germination of the parasite. If applied, this 
plaster may be removed in forty-eight hours. The following 
is what is then observed : 
The sown surface, which was a little moist at the moment 
when the plaster was taken off, soon dries ; the epidermis is 
regenerated ; but instead of forming a continuous layer* 
smooth and adherent, it becomes detached, and comes away, 
during several days, in the shape of furfuraceous scales of 
variable sizes. From the eighth to the twelfth day we begin 
to distinguish, on the surface where the favus dust had been 
deposited, some little tubercles the size of a pin-head, a grain 
of millet, or, at the most, a small lentil, little prominent, but 
hard to the touch, and of a grayish colour. At first hemi- 
spherical, these tubercles soon become depressed at their 
centre, while their borders rise and give them a more or less 
marked cupuliform aspect. These are veritable favi, tra- 
versed by a little tuft of bristly hair, and which only differ 
from the favi already described by their remaining a long 
time of a dull gray tint. 
If this primary favus crust be removed it is reproduced 
very rapidly, sometimes by the following morning ; this 
second crust exhibits, very distinctly, the characteristic 
sulphur-yellow hue. Otherwise, in the primary crust, as in 
that which succeeds it, there is found, on a microscopical 
examination, the same elements — mycelium, sporophorous 
tubes, and spores — noticed in the Tinea crusts, as they are 
presented in clinical observation — elements which may also, 
as I have assured myself by experiment, prove capable of 
producing the disease. 
With time these favi increase ; others are developed in 
their vicinity ; the nearest soon touch by their margins, and 
then they become deformed ; at times their central depression 
is obliterated by the incessant accumulation of new crypto- 
gamic elements, and the cupuliform aspect disappears ; but it 
is very rare that we do not witness it sharply defined on the 
borders of the affected part. 
Relations of the Tinea of animals to the Tinea of man. 
xliv. 58 
