Etiology, Pathogenicity. 391 



Lipsehiitz describes the bodies of contagious pleuro-pneumonia as roundish 

 protoplasmic clumps almost %/u. in size which occur single or in pairs, or, 

 though rarely, in numerous chains containing 3-4 segments, lying close to each other. 

 Plump forms with angular borders may be also found (degenerated elements?). 



According to Bordet spirochEetes resembling the organism of syphilis develop 

 on blood-potato agar, and also in transfers to alkaline peptone bouillon contain- 

 ing rabbit serum, they are however much shorter and finer spirillae. Borrel ob- 

 served in preparations obtained according to Lbffier 's mordant method, a pronounced 

 pleomorphic appearance of the virus. According to his and his co-workers' findings, 

 pure cultures consist of cocci, streptococci, and morula-shaped bodies, further short, 

 spiral threads, which show fork-shaped branchings, and asteroid figures as well as 

 mycelioid moulds, and are always surrounded by fine, mucin coverings. On account 

 of its last-named properties he called it asterococcus mykoides. 



Staining. In bouillon cultures the bodies may be stained with 

 aqueous, and still better with aniline dyes containing carbolic acid; 

 also with Loffler's flagella stain, and according to Giemsa's method, 

 while they cannot be stained by Gram's method. 



Cultivation. Nocard & Roux cultivated the virus by placing a 

 mixture of bouillon and a small quantity of lymph from the lungs in 

 collodion sacks and sewing these into the abdominal cavity of rabbits. 

 By such a procedure the bacteria are protected from the phagocytes; 

 and the bouillon is rendered more suitable for the propagation of the 

 virus by osmosis between it and the peritoneal fluid. After 15 to 20 

 days the fluid became cloudy and opalescent, and the above mentioned 

 small granules were, on microscopical examination, found present in 

 great numbers. 



Later the cultivation succeeded by a similar procedure in the 

 abdominal cavity of cattle (not in guinea pigs) also in Martin's bouil- 

 lon, to which had been added blood serum from cattle or rabbits (6 to 

 8%). Outside of the animal body they may be cultivated on agar pre- 

 pared with such bouillon, the surface of which has been moistened with 

 a few drops of serum (Dujardin-Beaumetz) as well as in Loffler's 

 bouillon containing 25% cattle blood serum (Schmidt). In bouillon 

 the culture is noticeable after 2 to 3 days by a very delicate turbidity 

 of the fluid, while on agar the colonies form very fine transparent, later 

 whitish points adherent to the surface of the medium. The optimum 

 temperature is 37° to 38° ; below 30° the growth ceases. 



Tenacity. Cultures kept in the thermostat and transferred every two weeks, 

 retain their unattenuated virulence not longer than 6 to 8 days, while in glass tubes 

 closed by melting at the ends, and kept at a temperature not exceeding 12°, they 

 retain their virulence for almost a year (Nocard, Eoux & Beaumetz).- 



The fluid from the lungs remains virulent for eight days if kept in a cool 

 place; after a month the virulence has become attenuated, in the air and in sun- 

 light, however, the attenuation occurs much earlier. A temperature of 58° destroys 

 the virus, while frozen pieces of lungs kept at a temperature of — 5° to — 6° 

 contain virulent lymph even after three months (Laquerriire). The virulence is not 

 influenced by concentrated glycerin, nor by 0.5% carbolic acid (Schiitz & Steffen, 

 Nocard). 



Pathogenicity. After the subcutaneous inoculation of a few 

 drops to 10 cc. of pure culture into the subcutaneous connective 

 tissue of the rump or neck of cattle, the temperature commences 

 to rise after 6 to 27 days. Soon an edematous swelling develops 

 starting at the point of inoculation, and finally the animal dies, 

 when the autopsy reveals a pronounced serous infiltration of 

 the subcutaneous and intramuscular connective tissue; or the 

 swelling disappears after 1 to 2 weeks and the animal recovers. 



