PRACTICAL BACTERIOLOGY. 



or irregularly distributed througliout the tissue, so 

 that in nearly every section some will be seen. It is 

 distinctly more difficult to find the bacilli in other 

 organs, such as in the liver, the kidneys, or the spleen; 

 for although they occur generally in great numbers 

 in the spleen, they are not distributed throughout the 

 organ, but are collected together in large deposits, 

 which sometimes contain hundreds, or even thousands 

 of them, whilst other parts remain quite free, so that 

 very often a very great many sections may be cut in 

 which not a single bacillus can be seen.^ 



It is especially, difficult to demonstrate the presence 

 of the typhoid bacillus in drinking water, and, con- 

 sidering the number of experiments that have been 

 made, has been very rarely done. The methods for ex- 



' An intense coloration may be produced by the following 

 method, which is recommended by Mcolle, in the Annal&s de 

 rinsiitut Pasteur of Nov. 2Bth, 1892. Sections wbicb have 

 been dehydrated by means of alcohol are immersed for from 

 one to three minutes in a solution of Loffler's or Kuhne's 

 methylene blue. After having been rinsed with water, they 

 are treated with a ten per cent, solution of tannin, the action 

 of which is almost instantaneous. They are next rinsed with 

 water, dehydrated with absolute alcohol, and cleared with oil 

 of cloves or of bergamot. By this means the micro-organisms 

 are stained an intense blue, whilst the tissue is not over- 

 coloured. Excellent results have thus been obtained with 

 sections containing bacilli of typhoid, glanders, hog-cholera, 

 chicken cholera, and other bacteria which it is difficult to 

 stain intensely. 



