366 DISEASES OF CATTLE. 



(6) Some coal-tar products are cheap, effective, and easily applied 

 disinfectants, their action being due to the carbolic acid and creosote 

 in their composition. They ma}^ be used in 3 to 5 per cent solution. 

 As a rule they form a milky solution in watei*. 



(7) Compound solution of cresol (liquor cresolis compositus), 

 now recognized as an official preparation, is composed of equal parts 

 of cresol and linseed-oil-potash soap. The mixture is a thick, dark, 

 amber-colored fluid which mixes readily with water in all propor- 

 tions to form a clear, soap solution. It is an efficient disinfectant in 

 a 3 or 4 per cent solution, and in this strength it may be applied in 

 the same manner as a 5 per cent solution of carbolic acid. 



When it is desired to apply one of these above-mentioned agents to 

 the stable or barnyard, a preliminary cleaning up of all debris and 

 litter is advisable, together with the scraping of the floor, mangers, 

 and walls of the stable with hoes; also the removal of all dust and 

 filth. This should be followed by the burning of all such accumula- 

 tions, inasmuch as this material likewise contains the infectious prin- 

 ciple and is best destroyed by heat. Heat may be applied to the 

 surface of the affected pen, byre, or barnyard by means of a cyclone 

 burner, which consists of a tank, pump, hose, and cyclone nozzle for 

 spraying with paraffin (gas oil). The latter is ejected in the form of 

 spray, which when ignited gives a very hot and effective flame to be 

 applied to the infected ground. Where such burning is impracticable 

 the surface soil of the yard and surroundings should be removed to a 

 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 ex- 

 posed may then be sprinkled with the disinfectant. 



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, ex- 

 cepting 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 animals may be regarded as an ally of these de- 

 structive organisms. 



CONTAGIOUS PLEUROPNEUMONIA. 



[Pis. XXIX-XXXII.] 



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

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

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



