Natural Infection. 575 



abdomen). In such cases infection evidently occurs through the 

 medium of previously existing wounds. Infection of the sper- 

 matic cord doubtlessly occurs in this manner, the contagion prob- 

 ably being transmitted from the bedding, and finding a fertile 

 soil for development and propagation in the necrotic end of the 

 cord and in the retained products of inflammation (Chaussee). 

 In the internal organs botryomycotic changes "develop as 

 a rule as metastases resulting from superficial botryomycomata 

 on some other part of the body. In rare cases, however, they 

 may constitute primary lesions. Thus, in a case described by 

 Bollinger, the lungs and.the bronchi only were affected, indicat- 

 ing infection through the respiratory organs. In another case 

 (Eabe) a pelvic tumor communicated with the bladder by means 

 of a fistulous canal, possibly caused by catheterization.. Finally 

 the possibility that botryomyces, like actinomyces, may gain 

 entrance into the tissues' from the lumen of the intestine and 

 thence pass to other abdominal organs, does not seem excluded. 



Pathogenicity. The botryomyces constitute a tissue irri- 

 tant with a similar action to that of the actinomyces. They 

 cause the emigration of round cells which subsequently become 

 transformed into epithelioid and giant cells, although the emi- 

 gration of leucocytes is more rapid in infection with botryo- 

 myces, consequently the formation of pus is earlier evident. 

 Connective tissue proliferation also occurs in the region sur- 

 rounding the pus foci and leads to the formation of firm, fibroma- 

 like tumors. Finally this fungus may be distributed through the 

 lymph spaces, in exceptional cases also through the blood ves- 

 sels, and give rise to metastases in remote regions of the body. 



Anatomical Changes. Botryomycomata consist of tough, 

 firm, fibrous connective tissue, grayish-white or pale red on sec- 

 tion and lardaceous in appeara,nce, containing yellowish-red or 

 brownish-yellow gelatinous foci which project above the cut sur- 

 face and in which whitish-gray granules are embedded, the 

 latter even visible to the naked eye. Very large tumors may now 

 and then contain large cavities or fistulous canals filled with a 

 muco-purulent mass. Their tough walls are lined with yellowish- 

 red soft granulation tissue. 



These tumors are found, as a rule, in the subcutaneous con- 

 nective tissue and in the skin, occasionally also in the muscles. 

 In addition they are found quite frequently in the end of the 

 spermatic cord of geldings, in which cases they spread through 

 the inguinal canal to the peritoneum and may give rise to sec- 

 ondary tumor formation in the anterior portions of the abdom- 

 inal cavity (Schimmel). 



In the rare cases observed in the lungs, the latter organs 

 may contain one or more tumors that may have attained the size 

 of a man's head, and occasionally very numerous smaller tumors 

 approaching the size of a fist ; these are sharply circumscribed 



