90 
SOCIETY MEETINGS. 
ally, invades the subcutaneous areola and aponeurotic structures, 
and is followed by a sloughing of the portion of skin involved 
and the connective tissue beneath. 
In many cases the process resembles the suppurative termi¬ 
nation of a contused wound, plastic infiltration existing at first, 
followed by suppuration, which soon attacks the skin, which it 
perforates from within outward, exposing an irregular cavity in 
which the subcutaneous connective tissue is represented by masses 
of shreddy sloughs, soaked in a puriform fluid, mixed with coag¬ 
ulated lymph and blood. 
In regard to the causes which operate to produce these 
changes, there is but one which I can assign as the direct cause— 
and that is cold. I do not attribute it to low atmospheric tem¬ 
perature, nor to snow or ice—which do not produce a degree of 
cold greater than 32° Fahrenheit—but to artificial cold, caused 
by the admixture of salt with the snow in the streets. When 
salt is mixed with snow in equal parts, an extreme degree of cold 
is attained, the temperature being reduced from zero, Fahrenheit, 
to 18° below. The effect of such intense cold upon the integu¬ 
ments of a region so meagerly supplied with blood vessels, and so 
far away from the centre of circulation as the phalangeal region 
of the horse, can readily be imagined : congelation must follow, 
and gangrene is the result, the animal, in the great majority of 
cases, being taken from the streets into a hot stable where his 
feet and legs are surrounded with straw. Moreover, the effects 
of dry cold are much less injurious to the part where it is applied 
than cold associated with moisture, and it is to wet and cold at 
the same time that these horses’ feet are exposed. Although the 
various forms of eczematoses, familiarly known as “ scratches,” 
“ grease,” and “ chapping,” are met with during the entire win¬ 
ter, the deep sloughings to which I have alluded occur only while 
the streets contain snow and ice, which fact leads me to the con¬ 
clusion that excessive cold is the sole cause of their development. 
Pathology .—The effect of extreme cold on the animal body 
is to lower all vital activity. Whether this extinction of vitality 
is general or local depends upon whether the entire body or a 
portion only is exposed to its effects. The blood vessels of the 
