PRESERVATION OF SPECIMENS 117 



and then placed in the following solution for twenty-four to forty- 

 eight hours : 



Formalin ...... 6 parts 



Sodium chloride ..... 1 part 



Sodium sulphate ..... 2 parts 



Magnesium sulphate .... 2 parts 



Tap- water .... .100 parts 



After being taken from the formalin solution the specimens are 

 placed in methylated spirit for ten minutes, and then in a fresh 

 bath of methylated ; in this the colour to a large extent returns, 

 and they should be carefully watched and not allowed to remain 

 in it for more than an hour. They are then mounted in the 

 following mixture : 



Glycerine ...... 400 c.c. 



Potassium acetate ..... 200 grm. 



Water 2000 c.c. 



A trace of formalin should be added to this. 



The writer has preserved meat infected with B. prodigiosus very 

 satisfactorily by the following method. Slices were cut off and 

 placed in the formalin solution given above for a few hours. They 

 were then well drained and placed in suitable glass capsules. 

 Ordinary nutrient gelatin was melted and sufficient poured in to 

 cover the specimens, and when it had set a little formalin was 

 poured on and allowed to remain for a few days. It was then 

 poured off and the glass top cemented down. 



For further information on preparation of tissues, section cutting, 

 staining methods, etc., see The Microtomisfs Vade-Mecum, Bolles- 

 Lee ; Practical Histology, Schafer ; Methods of Morbid Histology 

 and Clinical Pathology, Walker Hall and Herxheimer ; and Lehrbuch 

 der Mikroskopischen Technik, Rawitz. 



