612 PATHOGENIC MICROORGANISMS 



animals. The most widely used method of producing such serum is that of 

 Maragliano. 



Maragliano's Serum. Q7 Maragliano believes that a toxalbumin is present 

 in tubercle-bacillus cultures which is destroyed by the heating employed in 

 the usual tuberculin production. He procures this substance by nitration 

 of unheated cultures and precipitation with alcohol (tossina prageipitata). 

 He furthermore makes an aqueous extract of the bacillary bodies. With these 

 two substances he immunizes horses. He draws blood from these after four 

 to six months of treatment. The serum is extensively used in Italy. Its 

 value is, at present, very doubtful. 



Marmorek's Serum. 68 Marmorek claims that the poisons produced by 

 Bacillus tuberculosis depend largely upon the medium on which it is grown. 

 He advanced the view in 1903 that the substances obtained in tuberculin 

 were not the true toxins of the tubercle bacillus, that there was a marked 

 difference between these and the poisons elaborated by a younger (primitive) 

 phase of the bacillus as it occurs only within the animal body or on media 

 composed of animal tissue. He consequently grows his cultures on a medium 

 composed of a leucotoxic serum (produced by inoculating calves with guinea- 

 pig leucocytes) and liver tissue. Such cultures, he claims, contain no tuber- 

 culin. To the sera produced by immunization with these cultures he attributes 

 high curative powers. 



We may say with considerable confidence at the present time that 

 no method of passive immunization in tuberculosis has, up to the pres- 

 ent, had any degree of success. 



Bacilli Closely Related to the Tuberculin Bacillus. The Bacillus of 

 Bovine Tuberculosis. Tuberculosis of cattle (Perlsucht) was studied 

 by Koch 69 in connection with his early work on human tuberculosis. 

 Koch 'did not fail to recognize differences between the reactions to 

 infection in the bovine type of the disease and that of man. He attrib- 

 uted these, however, to the nature of the infected subject rather than 

 to any differences in the infecting agents. This point of view met 

 with little authoritative contradiction, until Theobald Smith, 70 in 1898, 

 made a systematic comparative study of bacilli isolated from man and 



6T Maragliano, Eerl. klin. Woch., 1899; Soc. de biol., 1897. 



68 MarmoreJc, Berl. klin. Woch., 1903; p. 1108; Med. Klinik, 1906. 



69 Koch, Arb. a. d. kais. Gesimdheitsamt, 11, 1882. 



70 Th. Smith, Jour. Exp. Med., Ill, 1898. 



