MICROCOCCUS GONORRHCE^ 353 



When needed, the flask and its contents are heated to 

 50° C; from six to eight tubes of 2 per cent, peptone- 

 agar-agar are dissolved by boiling, brought to 50° C, 

 and then mixed with the solution in the flask and the mass 

 poured into Petri dishes. Upon the surface of this serum- 

 nitrose-agar the cultivation is to be conducted. Wassermann 

 lays particular stress upon two points that are essential to 

 success, viz., the preliminary boiling of the serum-nitrose 

 mixture before steam sterilization, as this prevents precipi- 

 tation of the albumin; and the necessity of having both 

 the serum-nitrose mixture and the agar-agar, to be mixed 

 with it, at not over 50° C, for if they are at a boiling tem- 

 perature when mixed, or if they are brought to the boiling 

 temperature after mixing, the albumin will be precipitated 

 notwithstanding the presence of the nitrose, which otherwise 

 prevents this. 



Wassermann further observes that some samples of serum 

 require to be more highly diluted with water than in the 

 proportions given above; that the agar-agar should be 

 feebly, but distinctly, alkaline to litmus, causing no red- 

 dening whatever of blue litmus paper; and, finally, that 

 the Petri dishes containing the solidified medium on which 

 the cultures are growing are best kept bottom upward, so 

 as to prevent water of condensation collecting on the surface. 

 By the use of the above medium he has cultivated the gono- 

 coccus from about one hundred different cases. 



Lipschiitz's Medium. — ^Lipschiitz'^ endeavored to find a 

 medium that could be prepared easily from substances 

 occurring in commerce. After testing a number of albu- 

 minous preparations of vegetable and animal origin, he 



' Centialblatt fiir Bacteriologie, Originale, Bd. xxxvi, 19Q4., 

 25 



