292 
THE CAUTERY AND THE SETON. 
into contact. These sloughs contain no foreign principles ; they 
are dry, solid, and formed of the organic elements of the part 
more or less carbonized. 
The second species of cautery, having for its object the intro- 
duction into the tissues of a certain quantity of caloric, without 
disorganizing them, can only be practised by means of the heated 
iron. 
It follows from this, that there are two species of cautery, the 
potential and the actual. The first are called potential, because 
their properties remain latent until they are placed in circum- 
stances adapted to bring them into play, i. e. until they are 
brought into contact with a living tissue, and because they do 
not act until some time after their application. The actual cau- 
teries differ from the potential, in that the principle of their acti- 
vity, which is free caloric, is in full exercise the very moment 
that they are brought into contact with animal matter. 
[Here follows a long account of the potential cauteries, which 
we omit.] 
Veterinary surgery often prefers the employment of the fire to 
that of the caustic. It acts more energetically and more rapidly 
on the tissues endowed with life, and imparts to them a peculiar 
stimulus, highly useful in a great variety of circumstances. The 
agents which we use in this species of cauterization are of two 
kinds ; they are themselves either artificially penetrated with an 
unusual quantity of caloric, or in the process of ignition they dis- 
engage a great quantity of it. The first are the actual cau- 
teries, properly speaking ; the second are different kinds of moxa. 
The actual cauteries are chiefly used in veterinary practice. It 
is generally allowed, at the present day, that the substances em- 
ployed in the construction of these cauteries are simple recipients 
of caloric, the only source of their virtue ; and that iron and steel, 
on account of their great capacity for caloric, and the facility 
with which they impart it, and their infusibility, and their mode- 
rate price, supersede the use of every thing else. Steel especially, 
on account of its superior density and less degree of oxydability, 
putting out of the question the alterations to which the surface 
of iron is subject, ought to be preferred to every other metal. In 
addition to these advantages, sufficiently great, iron and steel 
possess another, of the utmost importance in practice, and that is, 
of assuming, while they are penetrated by and parting with the 
matter of heat, successive tints, sufficiently distinct, and which 
indicate with the utmost precision the quantity of caloric with 
which they are charged. 
The cautery irons differ from each other in the form and size 
of the cauterizing surface alone. 
