376 DISEASES OF CATTLE. 



tant but it is likewise very poisonous, hence its uses are limited. A 

 solution of one-tenth per cent is usually sufficient (1 ounce to 15 gallons 

 water). It is corrosive, and hence metal pails and dishes are to be 

 avoided. All solutions should be labeled "poison," and to avoid acci- 

 dents none should be kept on hand. In general the three first men- 

 tioned are safer, and Nos. 2 and 3 equally powerful in the solutions 

 recommended. 



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 animals 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 animal s may b<J 

 regarded as an ally of these destructive organisms. 



CONTAGIOUS DISEASES. 



(Description of Plate 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 Friinkel 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 Wild- 

 seuche and Riuderseuche in Europe, and are closely related to swine-plague bacteria 

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



Fig. 2. Micrococci (staphylococcus) which produce inflammation and suppuration, 

 also pyaemia. 



Fig. 3. Micrococci (streptococcus) which produce inflammation of the liniug mem- 

 branes of the abdomen, thorax, heart, brain, and joints. Frequently associated 

 with the preceding bacteria in abscesses. 



Fig. 4. Bacilli of black quarter. The pale oval bodies as well as the light spots 

 in cue end of the bacilli represent spores. 



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

 ends of the rods represent a spore. 



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

 lining membrane of the chest cavity. The bacilli are stained 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. 



CONTAGIOUS PLEURO -PNEUMONIA. 



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 has been manifested in re- 

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

 from some foreign markets on account of its recent existence here, the 

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



