MILK 103 



tuberculosis, complete proof should always be obtained by 

 finding tubercle bacilli in the enlarged glands and other tuber- 

 culous lesions. 



The animal test for tuberculosis takes at least three weeks 

 before any diagnosis can be made. To shorten this period 

 Bloch 1 has suggested that the inguinal glands on the inoculated 

 side should be slightly damaged by squeezing them. He found 

 that in all positive cases the glands within 9 to 12 days were 

 markedly enlarged and tubercle bacilli present in large numbers 

 both in films and sections. The earlier development of tuber- 

 culosis is due to the greater growth in the slightly damaged 

 glands. This modified procedure has been found of value by 

 several other investigators. 



The possible presence in milk of acid-fast bacilli other than 

 the tubercle bacillus, while it diminishes the value of simple 

 microscopic examination, does not to any considerable extent 

 interfere with the inoculation test. The death of the guinea-pig, 

 with lesions apparently those of tuberculosis, is almost certainly 

 due to tubercle bacilli. As a routine procedure, and certainly in 

 any cases of doubt, cultures should be made on glycerine agar 

 from the enlarged glands. The simulating acid-fast bacilli grow 

 readily and rapidly upon this and other nutrient media, unlike 

 the tubercle bacillus. 



Since the acid-fast bacilli are of considerable importance in 

 relation to the diagnosis of tubercle bacilli in milk and milk 

 products a brief note of this group may be of assistance. 



The acid-fast bacilli are a group of organisms fairly widely 

 scattered in nature and mostly of no particular significance in 

 themselves but which owe their importance to the fact that 

 morphologically they somewhat closely resemble the tubercle 

 bacillus while also, like that bacillus, they resist decolorisation 

 by acids. 



Of recent years a number of such bacilli have been isolated 

 and studied of which the best known are the butter bacillus of 

 Rabinowitsch and Petri (see page 117), Moeller's timothy-grass 

 bacilli I and II, originally isolated saprophytically growing upon 

 this grass, Johne's bacillus the cause of Johne's disease (a form 



1 Berlin, klin. Wochenschr. 1907, Vol. XL, p. 511. 



