Lung Plague of Cattle. 603 



immunity of the United States since the last infected cattle were 

 destroyed in 1892, are equally conclusive in this respect. 



Bacteriology. The history of lung plague forcibly illustrates 

 how harmless microbes of large size, that may be easily dis- 

 covered, and which existing in the environment, readily find their 

 way into diseased and susceptible parts (in this case into the 

 bronchia), may be held to be the pathogenic cause. Willems 

 and Van Kempen, in 1852, found microbes in the exudate. 

 Lustig in 1885 found four separate microbes in the lesions, 1st, a 

 short, thick, liquefying bacillus to which he attributed the disease ; 

 and 2d, 3d, and 4th, three forms of micrococcus. Poels and 

 Nolen, in 1886, demonstrated bacilli of variable size (0.9/u,), 

 solitary, in pairs and chains, cultivable in different media, and 

 inoculable by injecting such cultures into the lungs, but the re- 

 sulting lesions were not marked by the full lung plague exudate. 

 Arloing, in 1887, separated from the exudate the bacillus lique- 

 faciens bovis, a very short, slender bacillus, often in pairs with 

 flagella, motile, staining easily in anilin but not in Gram's solu- 

 tion, quickly liquefying gelatine as a culture medium and as- 

 suming a form that might be taken for micrococci, quickly ob- 

 scuring peptonized bouillon, and growing on potato. The exu- 

 date placed in a thermostat at 95 F. encreases in potencj^. The 

 bouillon cultures injected under the skin or into the lung, produced 

 characteristic lesions of lung plague. 



In the light of the later experiments of Nocard and Roux in 

 1S97-8, it would appear that Arloing's bouillon cultures were prob- 

 ably complex, containing not only the bacillus liquefaciens bovis, but 

 also, the infinitesimal microbe which is the true cause of the lung 

 plague. In seeding culture media with the exudate taken with 

 all possible precaution against contamination, from the interlobu- 

 lar pulmonary connective tissue, they and others constantly failed 

 to obtain results. Better success attended their efforts with Mar- 

 tin's culture bouillon for producing diphtheritic toxin. Five 

 pigs' stomachs are minced, pounded to pulp, mixed as follows : 

 stomach 200 grs., pure muriatic acid 10 grs., water 5o°C, 

 1000 grs., left in a thermostat at 50°C. for 12 hours, (to 24), then 

 heated to ioo°, to destroy the action of the pepsin, then 

 lowered to 8o° C, alkalized, filtered from flocculi that formed, 

 heated to i20°C, and filtered. This is then mixed with pepton- 



