286 KENNEL DISEASES. 
erysipelas, especially since it is generally quite extensive; and frequently there 
are large patches of it here and there over the body; some also on the head 
and legs. 
Still another form of eczema is an exaggerated or severe type of this just 
described, the essential difference being in the size and number of crusts. That 
is, instead of the crusts being small, thin, and bran-like, they are much larger and 
thicker ; they are also far more abundant, and the skin beneath them is thicker 
and harder than in the other form. 
The last two and the papular are always dry forms, while the others are moist. 
Eczema may be acute or chronic. The latter is the most common. It is 
also by far the most severe and difficult to cure ; for while the former is usually 
limited to a few small patches of the eruption, this form is generally much more 
extensive, and may attack every portion of the body, head, and legs, and even 
the tail. 
As concerns the actual causes of eczema there is yet much to be learned. 
It has been considered by most non-professionals, also by physicians generally, 
to be a blood disorder, dependent upon faulty conditions of the stomach, liver, 
or other vital organs, although, of course, they have known that it may start 
with the application of external irritants. But recently, after long and care- 
ful study and observation, certain eminent specialists in skin diseases have 
announced their belief that it is a germ disease, and the true cause is the inocu- 
lation by a special organism or germ. 
If that is a fact, then the previously recognized causes of eczema are simply 
predisposing causes. That is, as such they prepare the way for the disease, and 
render the soil favorable for the development of the parasite which is its real 
cause. 
This theory is certainly within reason, but being in its infancy, —the micro- 
organism or germ, if there be one, yet to be discovered, and much else to be 
made clear before it can be accepted as positive, — the conditions and influences 
heretofore reputed to be real and exciting causes should be considered such 
until the etiology of old has been proved erroneous. It will also be quite safe 
to assume that if eczema is in some instances due to definite specific germs, in 
many others, germs have no part in the causation. 
The external causes of eczema are many and varied. It may be the imme- 
diate result of irritating the skin, as by scratching; by which means the eczema 
accompanying parasitic diseases is generated. Acrid medicated applications, 
as croton oil, tincture of iodine, strong mercurial ointments, liniments containing 
large proportions of ammonia, turpentine, and the like, highly alkaline soaps, 
etc., are capable of producing it. It may be caused by the long-continued 
heat of summer, also by extremes of temperature, and especially by too hot 
baths in subjects having very sensitive skins. Water alone even may cause it 
in non-water dogs if sent into it often and allowed to remain too long. 
