364 DISEASES OF CATTLE. 



depth of 5 or 6 inches and then placed in a heap and thoroughly 

 mixed with air-slaked lime. The fresh surface of the soil thus exposed 

 may then be sprinkled with any of the above-mentioned disinfectants. 

 In addition to these artificial substances there are several natural 

 sanitary agents of great importance as destroyers of virus. These are 

 cleanliness, ventilation, drying, and sunshine. All virus, excepting 

 such as may live in the soil, is killed sooner or later by drying and 

 sunshine, and the importance of these factors in the daily life of ani- 

 mals need not be insisted on here. Finally, all sanitary measures 

 which contribute to the healthfulness of animal surroundings are 

 directly or indirectly inimical to disease germs, and all carelessness 

 in the keeping of animals may be regarded as an ally of these destruc- 

 tive organisms. 



CONTAGIOUS PLETJRO-PNETJMONIA. 



Definition and history. — This disease has been eradicated from the 

 United States, and it is not probable that it will ever be seen in this 

 country again. As, however, much interest was manifested in regard 

 to it for a number of years, and as our cattle are still prohibited from 

 some foreign markets on account of its previous existence here, the 

 subject is treated at greater length than would otherwise be necessary. 



The contagious pleuro-pneuinonia of cattle is a specific epizootic 



VARIOUS BACTERIA WHICH PRODUCE BACTERIA IN CATTLE. 



[Description of PI. XXIX.] 



The bacteria on this plate are partly from tissues, partly from cultures, and 

 stained artificially with aniline colors (fuchsin or methylene blue). Figs. 6 and 7 

 are copied from Frankel and Pfeiffer's atlas. All but fig. 7 are magnified 1,000 

 times; fig. 7, 500 times. 



Fig. 1. Bacteria from pneumonia in cattle. These are also the cause of hemor- 

 rhagic septicemia and are closely related to swine-plague bacteria. These bacteria 

 were drawn from a piece of spleen pulp (rabbit) . 



Fig. 2. Micrococci (streptococcus) which produce inflammation of the lining 

 membranes of the abdomen, thorax, heart, brain, and joints. Frequently associ- 

 ated with the preceding bacteria in abscesses. 



Fig. 3. Micrococci (staphylococcus) which produce inflammation and suppura- 

 tion,. also pyemia. 



Fig. 4. Bacilli of blackleg. The pale oval bodies as well as the light spots in 

 one end of the bacilli represent spores. 



Fig. 5. Bacilli which produce tetanus, or lockjaw. The light spot in the enlarged 

 end of each rod represents a spore. 



Fig. 6. Bacilli of tuberculosis. Microscopic sections of a pearly nodule from 

 the lining membrane of the chest cavity. The bacilli are staked red and appear 

 as small straight rods within the cells of the nodule, or tubercle. 



Fig. 7. Bacilli of anthrax. Bacilli from the spleen of a mouse inoculated with 

 a culture. The bacilli were obtained from the blood of a cow which died of 

 anthrax in Mississippi. The bacilli appear as rods stained blue. The round bodies 

 are blood corpuscles, also stained artificially. 



