BACILLUS TYPHOSUS 499 



in diameter. Colonies of the colon or para-colon group 

 appear as larger, denser pink or red massses and cause 

 a reddening of the medium about them. 



All small, transparent, colorless colonies, i. e., those sug- 

 gestive of bacillus typhosus are to be isolated in pure cul- 

 ture and identified by the usual procedures. 



Precipitation Method of Ficker.' — Two liters of the water 

 to be examined are placed in a narrow sterile glass cylinder 

 and rendered alkaline with 8 c.c. of 10 per cent, sodium 

 carbonate solution, and afterward 7 c.c. of a 10 per cent, 

 sulphate of iron solution are added and mixed with the 

 water by means of a sterile glass rod. The cylinder is then 

 placed in the ice-chest. Precipitation is complete in two 

 to three hours. The overstanding water is syphoned off, 

 and the precipitate or portions thereof are poured into 

 sterile test-tubes. To this precipitate is now added about 

 ■ a half volume of a 25 per cent, solution of neutral potassium 

 tartrate. The test-tube is closed with a sterile rubber cork 

 and the mixture thoroughly agitated, whereby the precipi- 

 tate is completely dissolved. With a sterile pipette one part 

 of this fluid is mixed in a test-tube with two parts of sterile 

 bouillon, and this mixture is distributed over a series of 

 Drigalski-Conradi plates. Ficker advises when possible 

 the use of a centrifuge for the separation of the precipitate, 

 as he believes the results are likely to be more satisfactory. 



Prophylactic Vaccination. — That typhoid fever may be 



prevented by vaccination is an accomplished fact. Expe- 



r rience gathered during the past few years by all civilized 



governments, notably those of England, France, Germany 



and this country is unanimous in support of this statement. 



No argument could be more convincing than the results 



' Hygienisolie Rundschau, 1904, Bd. xiv, S. 7. 



