CULTURE MEDIA 



99 



Small amounts of sterile blood may be obtained frdm labora- 

 tory animals without killing them by means of heart puncture. 

 The needle of a Luer glass syringg is inserted through the chest 

 wall, after anesthetizing the animal and shaving and disinfecting 

 the skin, so as to enter the cavity of the right ventricle. A 

 quantity of blood not greater than y^o the weight of the animal 

 may be removed. The needle is withdrawn 

 and the blood (Juickly forced out into a sterile 

 tube where it may be defibrinated or mixed 

 with citrate solution, or allowed to clot, as 

 may be desired. 



Very large amounts of sterile blood are 

 best obtained from the juglar vein of the 

 horse or the superficial abdominal veins of 

 the cow. The skin is shaved, washed and 

 cauterized with 95 per cent carbolic acid. 

 When this has dried the vein is punctured 

 with the needle, which is attached to a 

 suitable glass receptacle by means of rubber 

 tubing. 



Collection of Sterile Ascitic Fluid.— 

 For this purpose a large trochar and canula 

 provided with a lateral outlet, and made so 

 that the trochar can be drawn back beyond 

 this outlet without being completely removed, 

 is most convenient. The instrument is oiled 

 with liquid paraffin. A rubber tube about pig- 38.— Pipette with 



■ 1 ^, . x^ 1 1 ^ i.1- i-T i. capillary tip for drawing 



40 cm. m length is attached to tne outlet Wdod from carotid artery 



and the whole is wrapped in a cloth and <^^") ^'^™^i- (^^'^'■ 

 sterilized in the autoclave. The site selected 

 for puncture should be cleansed and painted with tincture of iodine 

 and the skin may be frozen with ethyl chloride if desired. One 

 man inserts the trochar and canula, taking care not to contaminate 

 it after it is removed from the cover. Another manipulates the 

 attached rubber tube, carefully guarding it from contamination 



