CULTURE MEDIA 



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Dorset's Egg Medixun.^— Perfectly fresh eggs are washed and 

 the shells sterilized with bichloride solution. The eggs are then 

 carefully broken and the, yolks and whites mixed in a sterile 

 dish. The mixed material is poured into sterile tubes and solidi- 

 fied in the slanting position by heating at 70 — 75° C. for two 

 hours. Contamination with bacteria should be carefully avoided 

 throughout the preparation of the medium. The tubes should 

 be sealed with rubber caps or with wax and incubated for a 

 week before use. It is well to moisten the surface with a few 

 drops of sterile water from a pipette before inoculating. This 

 medium is used for growing the tubercle bacillus. 



Bread-paste. — Dry or toasted bread is broken into small 

 crumbs, filled into tubes or flasks, moistened with water and 

 sterilized in the autoclave. This medium is used for cultivation 

 of molds. 



Media Containing Uncooked Protein 



Culture media containing naturally sterile uncooked protein 

 have made possible the cultivation of microbic forms not cultivable 

 on other media. Many microbes which may also grow on cooked 

 media, do much better on those containing uncooked protein. It 

 would seem that media of this kind are to play an important part 

 in the further development of our knowledge of pathogenic 

 micro-organisms. 



Collection of Sterile Blood.^ — A few drops of blood may be ob- 

 tained from the ear lobe. The skin is cleansed with soap and 

 alcohol and then dried perfectly with sterile cotton. It is 

 punctured with a sterilized lancet and the blood quickly trans- 

 ferred to the surface of an agar slant by means of a platinum 

 loop or a sterile capillary pipette. It should be incubated before 

 use to insure sterility. 



Larger quantities of sterile human-blood may be obtained with 

 far less danger of contamination from the median basilic vein or 

 other large vein at the elbow. The skin is washed, disinfected 



' Dorset: American Medicine, April 5, 1902. -■ 



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