Natural Infection. g47 



tlie mncoiis membrane by means of a peculiar boring motion, 

 particularly by way of the excretory ducts of the salivary 

 glands or through the depressions on the surface of the tonsils 

 into the deeper tissues where they are firmly held by numerous 

 fine barbs, the contraction of the neighboring muscles serving 

 to draw them still deeper into the tissues. The characteristic 

 tissue changes may be observed to develop along the path of 

 invasion of the awn by subsequent irritation through the 

 fungus contained in the latter (this explains the frequently 

 observed metastases of the actinomycomata from the base of 

 the mouth cavity to the region under the skin of the inter- 

 maxillary space. The Ray fungus exists as a saprophyte on 

 grass and especially the various species of grains and accord- 

 ing to Bostrom has a special preference for the air tubes in 

 the stems of these plants. Its propagation is favored by damp 

 soil and moist atmospheric conditions, wdiile the considerable 

 resisting power of the spores insures the perpetuation of the 

 species under unfavorable climatic conditions. Infected plants, 

 especially barley, when fed dry, may produce injuries of the 

 mucous membranes and thus afford opportunity for the en- 

 trance of the fungus into the tissues. The disease is in fact 

 most frequently observed in winter, and in spring, correspond- 

 ing to the seasons of dry feeding. On the other hand a similar 

 entrance may be effected on pasture, particularly in stubble 

 fields, and give rise to infection at the lips. 



Brener observed actinomycosis during the latter portion of winter and early 

 part of the spring months (period of dry feeding) in 33% of adnlt animals, while 

 during the summer months only a frequency of 16% is recorded. Liebmann 

 observed the development of the Eay Fungus on wheat and barley straw that had 

 been grown on infected soil. Berestnew observed the development of the fungus 

 on the straw and heads of grains that had been kept moist for some time, while 

 according to Bang they have been observed to thrive on grains and straw, 

 particularly barley. According to Brazzola the fungus thrives most ' luxuriantly 

 on a certain species of wild barley. 



The enzootic development of the disease following feeding with 

 barley or barley straw points to the intermediary role plaj^ed by the 

 awns of barley in the dissemination of this disease. Thus on an estate 

 near the Danish seacoast the majority of a herd of cattle became affected 

 with actinomycosis after having been fed for some time with straw 

 and grain that had been grown on a drained area of the seacoast. At 

 a snbseriuent date when similar material was fed, the disease appeared 

 anew (Jensen). According to Nicolans the disease occurs in regions 

 of Silesia where barley is grown extensively, apparently ns a result of 

 the practice of feeding barley straw, especially chaff, without prelimi- 

 nary steaming or scalding. 



Barley awns have been found in the diseased tongues of cattle 

 as well as in the tonsils of swine and in a few instances ( Johne, Nenwirth, 

 Plana, Korsak) it was possible to demonstrate the presence of the Ray 

 fungus on the surface or in the interior of the awns as well as in the 

 surrounding tissues. 



Contrary to tlie P-enerally accepted view that the Ray fun^ns is 

 a saprophyte or facultative parasite, "Wright has expressed the opinion 



