and
injure the digestive tract. Grass eaten with frost on it may cause severe
indigestion. All moldy feeds are not injurious, for some molds appear to
have no influence on the process of digestion, but those of other species
may not only retard digestion and cause local injury to the digestive
organs, but may cause general poisoning of a severe and fatal type.

The following molds have been shown (Dammann) to be dangerous in respect to
the production of the morbid conditions enumerated:

_Tilletia caries_ grows chiefly in wheat and may be found with the grain,
thus appearing in the bran or meal. It causes paralysis of the throat and
spinal cord and irritation of the digestive tract. The rusts, such as
_Puccinia graminis_, _P. straminis_, _P. Coronata_, and _P. arudinacea_,
cause colic and diarrhea, and in some cases partial paralysis of the
throat. The rusts that occur on clovers, beans, and peas cause very severe
irritation of the lining membrane of the mouth and throat, resulting
sometimes in gangrene of this tissue.

_Polydesmus exitans_ grows on the leaves of rape and turnips, appearing in
early summer. This fungus is very irritating to the mouths and feet of
cattle, causing severe inflammation and the formation of a false membrane.
In some instances this condition has been mistaken for foot-and-mouth
disease, but it can be differentiated by the absence of the blister that
is characteristic of that disease and by the further fact that it is
nontransmissible.

_Polytrincium trifolii_, which grows on clover, causing it to become black,
causes severe irritation of the stomach and intestines of cattle feeding
upon it.

Feeds must not contain too large a proportion of woody fiber or of
indigestible substances. If the dry matter ingested or the bulk of the feed
is very great on account of the small proportion of digestible matter, it
is impossible for the great mass to be moistened properly with and attacked
by the digestive juices. In consequence of this, abnormal fermentations
arise, causing indigestion and irritation of the digestive organs. On the
other hand, a ration too concentrated, and especially too rich in protein,
is not suitable, because, after a meal, the animal must have a certain
feeling of fullness in order to be comfortable and quiet, and the digestive
organs require a relatively large volume of contents to fill them to the
point where secretion is properly stimulated and their activity is most
effi