258 PATHOGENIC BACTERIA IN MILK 



range, of temperature within which they flourish), and their feebler 

 pathogenic properties. From these facts it follows that however 

 great the degree of similarity between these various acid-fast 

 bacilli, and however much it is possible by artificial cultivation 

 to modify the morphology of the various forms, there is sufficient 

 difference to enable a differential diagnosis to be made if all the 

 biological characters are ascertained, and most of all the patho- 

 genic properties. Hence the importance of the inoculation test 

 being applied to all acid-fast and tubercle-like organisms detected 

 in milk or butter. 



The pathological differences from Koch's bacillus are that inocu- 

 lation with acid-fast bacilli gives rise to no " giant cells," no epithe- 

 lioid cell clusters, and no tuberculous caseation. Nodular lesions 

 occur suggestive of tubercle, but according, to Potet,^ and Abbot and 

 Gildersleive ^ : [a) they constitute a localised lesion only, having no 

 tendency to dissemination, metastasis, or progressive destruction 

 of tissue by caseation ; {Jj) they tend to terminate in suppuration 

 like ordinary abscesses ; {c) when occurring as result of intravenous 

 inoculation they appear in the kidney, rarely in the lung and other 

 organs ; {cT) the form of granuloma set up is similar to actinomyces. 



This group of organisms is one of considerable importance 

 to the milk bacteriologist, and in all investigations dealing with 

 the tubercle bacillus, or with milk and its products, it is essential 

 that the bacilli met with should be clearly differentiated from 

 the tubercle bacillus. Insufficient care has been taken in this 

 respect up to the present. Any such organism found should be 

 compared in cultural and pathogenic properties with the human 

 tubercle bacillus, the bovine bacillus of pseudo-tuberculosis, and the 

 various acid-fast organisms, and not simply accepted on tinctorial 

 properties as a tubercle bacillus. 



^ Etude sur les Bacteries dites Acidophites (Potet, Paris, 1902), pp. 188-194. 

 ^ The University of Pennsylvania Medical Bulletin^ }\xn&^ 1902. 



