216 BACTERIOLOGY FOR NURSES 



next procedure. Hanging drop preparations are made of a mix- 

 ture of the broth culture and a dilution of immune horse serum, 

 the strength of which is already known. With appropriate dilu- 

 tions agglutination will take place almost immediately if the or- 

 ganism tested is the typhoid bacillus. The result may be confirmed 

 by inoculating media containing lactose and dextrose. Acid pro- 

 duction will take place in the latter and no change in the former. 



Vaccines. Wonderfully good results have been obtained from 

 the injection of killed bacilli as a prophylactic measure against 

 typhoid fever both in military and civil life. Statistics show a 

 steady- decline of typhoid in the U. S. Army since the introduc- 

 tion of compulsory vaccination in 1910. Only one case occurred 

 in 1913 among over 80,000 men. In the British Army the reduc- 

 tion of morbidity is estimated at 50 per cent. An excessive dose 

 of infectious material may break down the protection resulting 

 from the action of the vaccine, yet in such cases the severity of the 

 disease will be considerably modified. 



In the army 500 million, 1 billion, and 10 billion bacteria are 

 given usually on three successive Saturdays by means of a sub- 

 cutaneous injection near the insertion of the deltoid muscle. Oc- 

 casionally a slight local inflammation and a general feeling of 

 malaise develops which disappears within twenty-four to forty- 

 eight hours. Consequently it is customary to give the vaccine in 

 the afternoon so that any reaction which may develop will occur 

 while the individual is in bed. The degree of immunity decreases 

 after two and a half years. It is advisable, however, in cases of 

 constant strain and exposure to revaccinate each year. 



Attempts have been made to use small doses of vaccine as a 

 therapeutic measure in typhoid fever. Excellent results are 

 reported in a certain number of cases; in others, however, they 

 have been unsatisfactory. 



THE DYSENTERY GROUP 



The term dysentery is usually applied to diseases which show 

 such symptoms as intestinal pain and diarrhea with mucus and 



