332 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



Ventilated Dish for Bacterial Cultures.*— G. C. Whipple has de- 

 vised a ventilated dish (see fig. 59), the cover of which is supported 

 about 2 mm. above the lower plate by means of three projections. These 

 projections are indentations in the glass cover, and are obtained by heat- 



Fin. 



W 



^sT 



32 



•S 



J 



ing the edge and pressing the softened glass with a sharp point. The 

 sides of the cover are made deeper than in the Petri dish by an amount 

 equal to that which the cover is raised above the dish. With the cover 

 thus elevated these obtain free circulation of air. These dishes are 

 suitable for anaerobic as well as aerobic cultivations. 



Incoagulable Blood as a Culture-Medium.t — F.J. Bosc recom- 

 mends incoagulable blood for the cultivation of certain parasites, such 

 as Coccidium oviforme, and those of cancer, vaccinia, and syphilis. Blood 

 is rendered incoagulable by means of extract of leech-heads. The 

 powdered extract obtained by hardening the leech-heads in absolute 

 alcohol is boiled with water, and after filtration is preserved in sterilised 

 bottles. It is used either by adding it to the drawn blood, or by injecting 

 it into the veins of animals. 



Medium for Cultivating Chromogenic Bacteria. J — F. M. Chamot 

 and G. Thiry recommend the following procedure for the cultivation of 

 chromogenic bacteria. Large potatoes, and such as are known to become 

 mealy and porous on boiling, are selected. These are boiled with their 

 skins on till cooked through. The water is then poured off and the 

 potatoes allowed to cool, after which they are peeled and cut into slices 

 1 to 2 cm. thick. The slices are immersed for about 18 hours in a 

 dilute solution of sodium hydroxide. The slices are drained and then 

 transferred to covered glass capsules (100 mm. diam. and 50 mm. deep) ; 

 a little water is added, and the medium steam-sterilised on three succes- 

 sive days. The strength of the sodium hydroxide solution is given as 



* Journ. Applied Microscopy, iv. (1901) pp. 1197-8. 

 t O.K. Soc. de Biol de Paris, Hi. (1900) pp. 1052-5. 

 X Hot. Gazette, xxx. (1900) pp. 380-2. 



