Medical Botany. A 
it is found, is considerably various, and especially, that its 
own proximate principles, differ from every thing hitherto 
obtamed from the vegetable kingdem. 
The second opinion is, that the Clavus is an excrescence 
produced by the sting, and deposition of the eggs of an 
insect. : 
As there is no analogy in any respect, between this arti- 
cle, and such excrescences as are demonstrably occasioned 
_ by insects, this opinion must have originated from the fact, 
that the Clavus is occasionally found to be eaten by minute 
worms, and that small Jarve of insects, have been detected 
in it, which on being preserved, afterwards hatched into 
moths, or butterflies. ‘These occurrences are however too 
rare to establish the hypothesis, to which they seem to have 
given rise, and our inevitable conclusion must be, that they 
are only accidental. 
The third, (and only opinion which appears to be well 
supported,) is that the Clavus is a parasitic Fungus, like the 
different sorts of blight, smut, &c. 
The correctness of this appears to me, to be fully estab- 
lished, by the following considerations. 
First. This article has, exactly, all the physical charac- 
ters, such as colours, form, taste, smell, &c. and even the 
casualties incident to Sclerotium, a genus of Fungi. This 
genus consists of small solid fungous bodies, of a rounded, 
oval, or elongated form, their interior substance hard, occa- 
sionally almost as much so, as wood, sometimes a litle 
fleshy, always white or inclining to white; the outer skin 
in an early stage, is smooth, in a more advanced one often 
a little wrinkled, usually black, sometimes of a dingy pur- 
ple, seldom yellow, or white, in several species, covered by 
a peculiar kind of dust, or efflorescence, of the same colour ~ 
as the surface. 
Second. It has, like the several species of Sclerotium, an 
appointed place of growth. Some of these, as we are in- 
formed, are subterraneous, on the roots of mosses, or in the 
mass of tan, in bark-beds, in close damp places screened 
from the light, as under moss heaps, or upon the surface of 
the ground under the droppings of cattle, on the nerves of 
cabbages stored under ground, upon the leaves and branches 
of plants that are beginning to decay, on the fading foliage of 
trees, on the rind of living fruits, on the receptacle of com- 
