46 METHODS OF CULTIVATION OF BACTERIA. 



streptococci, but Marmorek has succeeded in doing so by grow- 

 ing them on the following media, which are arranged in the 

 order of their utility : 



1. Human serum 2 parts, bouillon I part. 



2. Pleuritic or ascitic serum I part, bouillon 2 parts. 



3. Asses' or.mules' serum 2 parts, bouillon i part. 



4. Horse serum 2 parts, bouillon i part. 



Human serum can be obtained from the blood shed in 

 venesection, the same precautions being taken as in the case of 

 that got in the slaughter-house. In the case of these media, 

 sterilisation is effected by method B (4), and they are used fluid. 



Hiss's Serum Media. Their use is for a more efficient 

 means of differentiating pneumococcus from streptococcus pyo- 

 genes, and they bear some resemblance to those of Marmorek. 



A. Ox serum i part. 

 Distilled water 2 parts. 



Normal sodium hydrate o. i per cent. 



B. Ox serum i part. 

 Distilled water 2 parts. 

 Inulin i.o per cent. 



They can be sterilised intermittently at 100 C. without 

 coagulating. In either medium pneumococcus forms acid and 

 coagulates the serum, but more rapidly in the latter, whilst 

 streptococcus does neither. 



Potatoes as Culture Material. 



(a) In Potato Jars. The jar consists of a round, shallow, 

 glass vessel with a similar cover (vide Fig. 1 1 ). It is washed 



with i-iooo corrosive sublimate, and a 

 piece of circular filter paper, moistened 

 with the same, is laid in its bottom. On 

 this latter are placed four sterile watch- 

 glasses. Two firm, healthy, small, 

 round potatoes, as free from eyes as 



FIG. ii. -Potato jar. possible, and with the skin whole, are 



scrubbed well with a brush under the tap 



and steeped for two or three hours in i-iooo corrosive sublimate. 

 They are steamed in the Koch's steriliser for thirty minutes or 



