122 STUDY AND IDENTIFICATION OF BACTERIA 



antitoxic power. Wright's method of prophylactic inoculation is now being em- 

 ployed in the British army with apparent success. In this, twenty-four- to forty- 

 eight-hour-old cultures are killed at 53C.; K% f lysol is then added. An injec- 

 tion of 500,000,000 bacteria is made at the first inoculation, and ten days later an 

 injection of 1,000,000,000. The British prefer to inject subcutaneously in the in- 

 fraclavicular region and at the insertion of the deltoid. The Germans consider 3 

 injections as conferring greater immunity. 



Russell has obtained splendid results in the U. S. Army with his method of 

 vaccination. In this 3 injections are given at intervals of ten days, the dosage 

 being 500,000,000, for the first and 1,000,000,000 for each of the 2 succeeding 

 injections. 



Typhoid vaccines sterilized with 0.5% of phenol appear to keep much longer and 

 to have a higher immunizing power than those prepared by sterilization with heat 

 and subsequent addition of the antiseptic. 



Typhoid bacilli may be found not only in the blood, urine and faeces but as well 

 in the sputum of cases showing pulmonary involvement. They have also been found 

 in the cerebrospinal fluid of cases showing meningeal symptoms. At the autopsy 

 they may be found in the spleen, Pyer's patches, mesenteric glands and liver. 



A very important discovery is that certain persons, who may have had only a 

 slight febrile attack, may eliminate typhoid bacilli for years in their faeces (typhoid 

 carriers) . The bacilli are also eliminated for considerable periods in the urine. Dis- 

 tinction is now being made between acute carriers (convalescents) and chronic 

 carriers. 



In experiments on higher apes there was evidence that the bacilli eliminated by 

 carriers are in many instances nonpathogenic. About one-half of typhoid cases are 

 believed to be due to contact infections. Drigalski gives it for Germany as 64.7%. 

 The water transmission factor is of less importance than was formerly stated. 



The most satisfactory method of detecting carriers is by examination 

 of faeces or urine plated out on Endo's medium. While carriers usually 

 give a Widal reaction this is by no means constant. Typhoid carriers 

 are said to maintain a high opsonic index. 



The urine and faeces of typhoid convalescents should be proven negative by cul- 

 tural procedure before discharging the patients. 



Vaccination may possibly be a satisfactory measure in bringing about the dis- 

 appearance of typhoid bacilli in the dejecta of carriers. 



For laboratory diagnosis, blood cultures during the first week and 

 agglutination tests during the second week and onward are the practical 

 methods. 



Along with the agglutination tests the urine and faeces should be cultured on 

 Endo's plating medium and later transferred to Russell's medium for cultural 

 identification. The positive identification, provided the culture so isolated shows the 

 cultural characteristics of typhoid, is made by testing the bacilli for agglutination 

 with a known typhoid serum. Instead of the usual blood cultures one may use the 





