TOXIC PRODUCTS OF B. TYPHOSUS 377 



and glands, and the spleen. These results are interesting, but 

 have not been confirmed. 



The Toxic Products of the Typhoid Bacillus. Here very 

 little light has been thrown on the pathology of the disease, but 

 the general results may be outlined. We may state that there 

 exist in the bodies of typhoid bacilli toxic substances, that in 

 artificial cultures these do not pass to any great degree out into 

 the surrounding medium, and that though they produce effects 

 on the intestine, there is evidence that such effects are not 

 characteristic and not peculiar to the toxins of the b. typhosus. 

 Sidney Martin found that the bodies of bacteria killed by chloro- 

 form vapour were very toxic, more so than filtered cultures. 

 Diarrhoea was a constant symptom after injection, but no change 

 in the Peyerian patches was observed. He also found that 

 virulent cultures of the b. coli gave similar results when 

 similarly treated. Allan Macfadyen, by grinding up typhoid 

 bacilli frozen solid by liquid air, produced a fluid whose toxic 

 effect he attributed to the presence of the intracellular poisons. 



The Immunisation of Animals against the Typhoid 

 Bacillus. Earlier observers had been successful in accustoming 

 mice to the typhoid bacillus by the successive injections of 

 small and gradually increasing doses of living cultures of the 

 bacillus. Later, Brieger, Kitasato, and Wassermann found that 

 the bacillus when modified by being grown in a bouillon made 

 from an extract of the thymus gland no longer killed mice 

 and guinea-pigs. These animals after injection were moreover 

 immune, and it was also found that the serum of a guinea- 

 pig thus immunised could, if transferred to another guinea-pig, 

 protect the latter from the subsequent injection of a dose of 

 typhoid bacilli to which it would naturally succumb. Chante- 

 messe and Widal, Sanarelli, and also Pfeiffer, succeeded in 

 immunising guinea-pigs against the subsequent intraperitoneal 

 injection of virulent living typhoid bacilli, by repeated and 

 gradually increasing intraperitoneal or subcutaneous doses of 

 dead typhoid cultures in bouillon. Experiments performed with 

 serum derived from typhoid patients and convalescents indicate 

 that similar effects occur in those who have successfully resisted 

 the natural disease. The serum of such patients has antibacterial 

 powers, but there is no evidence that it contains any antitoxic 

 bodies (see chapter on Immunity). Pfeiffer, for example, found 

 on adding serum from typhoid convalescents to typhoid bacilli 

 killed by heat, and injecting the mixture into guinea-pigs, that 

 death took place as in control animals which had received these 

 toxic agents alone. Pfeiffer also found that by using the serum 



