DISEASES OF THE DIGESTIVE ORGANS. 13 



The following molds Lave been shown (Dammann) to be danger- 

 ous in respect to the production of the morbid conditions enumer- 

 ated: 



TiUetia cartes 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 Puccinla g'taminis, P. strnmhits, P. C'oronafa, and P. 

 uriindinacea, 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, ap- 

 pearing in early summer. This fungus is very irritating to the 

 inouths and feet of cattle, causing severe inflammation and the for- 

 mation 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. 



Polytriiicium 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 

 ])roperly with and attacked by the digestive juices. In consequence 

 of this, abnormal fermentations arise, causing indigestion and irri- 

 tation of the digestive organs. On the other hand, a ration too con- 

 centrated, and especiallj' too rich in protein, is not suitable, because, 

 after a meal, the a.nimal 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 efKcient. 

 If too much protein is in the ration there is a waste of expensive 

 feed, and the tendency is for the animal to become thin. It is evi- 

 dent that a cow can not thrive on concentrated feeds alone, even 

 ihough these contain in assimilable form all the nutritive materials 

 needed for perfect support. It is because bulk is necessary that the 

 standard of about 25 pounds of dry matter per cow per day lias 

 been reached by experimenters. There is no objection to feeding 

 grain or meal separately to a cow, provided enough bulky feed is 

 fed at another time in the day to keep the digestive tract sufficiently 

 distended. 



In changing the ration, and especially in making radical changes, 

 as at the beginning and the end of the pasturing season, the change 



