Staining and Mounting Micro- Organisms. 83 



mixture will take up, and let it stand for six weeks. Filter, 

 and keep in an outside stoppered bottle. 



The above is difficult to make ; it is better to obtain it 

 ready for use. 



Glycerine Jelly. Dissolve 1 ounce of French gelatine in 

 6 ounces of distilled water ; then melt in a water-bath, and 

 add 4 ounces of glycerine and a few drops of creasote or 

 carbolic acid. Filter through paper while warm, and keep 

 in a stoppered bottle. The above may be used instead of 

 Farrant's medium. The jelly must, of course, be warmed 

 before use. All tissues or sections must be well soaked in 

 water before they are mounted fn Farrant's medium or 

 glycerine jelly, so that all trace of alcohol is removed. 



Tissues containing much air should be soaked in water 

 that has been boiled for about ten minutes and allowed to 

 cool. 



LESSON 5. 



STAINING AND MOUNTING MICRO- 

 ORGANISMS. 



The investigation of bacteria may be carried out under 

 various conditions : 



(1) In fluids, such as milk, water, blood, pus, etc. 

 (2) On solid media, bread, meat, potatoes, meat jelly, 

 etc., or in the tissues and organs of animals. In the former 

 case a drop of the fluid is placed on the centre of a cover- 

 glass and another cover-glass is placed on it; the two 

 glasses are then to be rubbed together to spread the 

 organisms evenly over their surfaces ; the} 7 are then 

 separated and allowed to dry. When bacteria are growing 

 on solid material, scrape oft* a small portion, put on a cover- 

 glass, and treat as above ; separate the covers, and allow 

 to dry. When the cover is quite dry, take it up with 

 a pair of forceps, organisms uppermost, and pass two or 



