616 KAYMOND A. KELSER 



the inside of the press in order that the pulp may not be 

 pressed through. The residue is then discarded and the fluid 

 placed over the flame and again brought to a boil, the coagu- 

 lated protein being skinmied off as it collects on the surface. 

 A sufficient amount of concentrated acetic acid (approximately 

 0.5 cc. per Hter of fluid) to cause flocculation is added, and 

 the boiling continued for five minutes. The product is now 

 ready to be filtered. For this purpose a stand is arranged hold- 

 ing three funnels, placed one above the other, the first con- 

 taining absorbent cotton and the other two filter paper, and the 

 material is filtered. The volume is then ascertained and 1 per 

 cent peptone and 0.5 per cent sodium chloride are added, heat- 

 ing sufficiently to effect solution. The medium can now be 

 titrated and the reaction corrected by neutralizing with sodium 

 hydroxide, or if a solid medium is to be prepared the usual 

 amount of agar may be added before titration. Sterilization 

 is accomplished by autoclaving for one-half hour under 12 

 pounds pressure. 



While the clot and the serum may be handled separately, 

 i.e., by removing the clot, cutting it up and boiling with dis- 

 tilled water, filtering, then adding the serum and again boiling, 

 this is not essential, as equally good results are obtained by 

 handling the clot and serum together. 



In the use of the bouillon alone I have found that the addi- 

 tion of a shght amount of carbohydrate (0.25 per cent glucose) 

 favors the growth of some organisms is this medium. This 

 is undoubtedly due to the fact that bouillon prepared from the 

 blood is almost sugar-free, containing only a few hundredths 

 of 1 per cent sugar. When agar is added the addition of carbo- 

 hydrate is unnecessary. 



The nitrogen content is also somewhat less in the blood 

 medium than in that prepared from beef. 



Several tests were undertaken to ascertain the comparative 

 value of this medium and that prepared from beef. Tubes of 

 bouillon, plain and glycerin agar were prepared from the blood 

 bouillon and the same from beef bouillon and inoculated with 

 various types of organisms, including streptococci, staphylococci, 



