ive how a microbe may cease such existence and assume parasitic or
pathogenic properties when the surroundings are eminently favorable. This
may be a connecting link in the etiology of sporadic outbreaks of the
disease in which all other hypotheses as to its genesis seem untenable. The
disease seems to occur most frequently in swampy or mucky localities or in
pastures receiving the overflow from infected fields. It is said to occur
usually in the spring of the year, when the melting snows and rains bring
to the surface the subterranean waters from rich soils containing
nitrogenous materials in which the bacteria have been existing. In a great
many instances there does not seem to be any plausible explanation for an
outbreak of the disease and one can only surmise as to its origin.

_Symptoms._--Three forms of the disease are recognized, based upon the
distribution of the lesions--the superficial, or cutaneous, the pectoral,
or thoracic, and the intestinal form. The last is a usual accompaniment of
the other two and may be mild or severe. Naturally the symptoms vary
according to the violence of the attack and to the particular form of
disease with which the animal is affected. In the superficial, or
cutaneous, form the presence of a swollen tongue, throat, and dewlap, or
even of the lower portion of the legs, gives us a clew to the trouble. An
entire loss of appetite occurs, and in milk cows there is a diminution of
the milk secretion. The temperature may be only slightly elevated, but it
is usually very high. Salivation is set up by the inflammation of the mouth
and pharynx. Unsuccessful efforts at eating and swallowing are made. There
may be difficulty in breathing, depending on the amount of involvement of
the larynx, trachea, bronchi, or lungs. There may be a blood-stained
discharge from the nostrils, and the mucous membrane thereof will often
show punctiform hemorrhages. The pulmonary form shows the same symptoms as
croupous pneumonia, with a frequent suffocative cough and oppressed
breathing, or dyspnea. When the intestines are involved the patient strains
to defecate, and passes shreds of intestinal mucus along with blood-stained
feces. The urine also may be tinged with blood. Finally a severe diarrhea
takes place, the animal becomes correspondingly weak, and death takes place
in 24 to 36 hours. Cases may die in as short a period as six to eight
hours, while in the pectoral form of the disease the animal may linger s