334 THE ALCALIGENES DYSENTERY TYPHOID 



repeatedly, then re-emulsified in normal saline solution and heated 

 to 50 C. for thirty minutes, then standardized in the usual manner. 

 Nearly eight hundred people have been vaccinated with these sen- 

 sitized living cultures; the local reaction was slight in each instance, 

 and only exceptionally was there any general reaction. A careful 

 examination of the blood, urine and feces of sixty-four of these cases 

 failed to show typhoid bacilli, which would suggest that individuals 

 vaccinated with living typhoid bacilli neither develop typhoid fever 

 nor become carriers. The cases are too few in number to compare 

 statistically with the cases vaccinated with killed cultures. Gay and 

 Claypole 1 have taken issue with Metchnikoff upon this point and their 

 experiments indicate that their sensitized dried vaccine may be 

 equally or more efficient without the theoretical dangers which attend 

 the use of living bacilli. 



Various attempts have been made to induce passive immunity to 

 typhoid infection by the injection of sera obtained from horses which 

 have received numerous injections of typhoid bacilli or their soluble 

 products. The results have on the whole not been encouraging. Gay 

 and Force 2 have applied a preparation of typhoid bacilli ("typhoidin") 

 made like Koch's old tuberculin, by the von Pirquet method, to 

 patients that have recovered from typhoid fever and to those who have 

 been vaccinated with typhoid bacilli. They find that 95 per cent, of 

 recovered cases from typhoid (20 cases out of 21 examined) gave a 

 clear-cut cutaneous reaction. One case had typhoid forty-one years 

 previously. The reaction was negative in 85 per cent, of individuals 

 not giving a history of typhoid (and presumably not vaccinated) 41 

 cases tested. The 9 cases (15 per cent.) that gave a positive reaction 

 were suspected to have had a mild undiagnosed attack. Several, 

 but not all, of those vaccinated within four years (9 out of 15) gave 

 a positive reaction. Gay and Force suggest that the test is of 

 presumptive value as an index of protection against typhoid by 

 vaccination. Later observations by them confirm this view. 



Diagnosis. The diagnosis of typhoid fever in the living subject may 

 be made either by the isolation and identification of the specific organ- 

 ism, Bacillus typhosus, or by the demonstration of antibodies specific 

 for this organism in the body fluids of the patient. 



(a) BACTERIOLOGICAL DIAGNOSIS. 1. Isolation of typhoid bacilli 

 from the blood stream and from rose spots. 



1 Loc. cit. 



2 University of California Publications in Pathology, 1913, ii, No. 14; Arch. Int, Med. f 

 1914, xiii, 471. 



