566 SUMMAEY OF CUEKENT RESEAECHES RELATING TO 



oculatecl into the upper stratum of a deep pyrogallol serum tube. The 

 tubes are left for several days at 37° C. The top layers of serum 

 undergo hquefaction,' but the upper part of the medium which still 

 remains solid may be rich in spirochetes. If this be so, the liquefied 

 serum is pipetted off, and portions of the spirochfete-containing zone are 

 iuoculated into fresh tubes. Pure spirochsete cultures so obtained do 

 not survive unless they are allowed to grow in symbiosis with typhoid 

 bacilli or Bacillus mesentericus . Abundant cultures of spirochaetes are 

 obtained by means of such artificial symbiosis. 



New Methods for the Culture of Bacteria.* — For the investiga- 

 tion of the action of nucleo-proteins and of cytoplasmic radicals upon 

 known bacteria and parasites, and for researches upon an unknown virus 

 which produces a specific effect upon a given organ, G. Mann recommends 

 the use of organ extracts prepared by a special method. Brain, liver or 

 skin, freed from blood to eliminate bactericidal principles, are passed 

 through a steriHzed mincing machine and the minced material placed in 

 an Erlenmeyer flask of known weight. To every gram of organ, 2 c.cm. 

 of sterile distilled water are added, and 10 c.cm. of chloroform to every 

 100 grammes of mixture. The flask is stoppered, and incubated for 

 varying periods at 37° C, being shaken daily. The supernatant fluid is 

 filtered through sterile barium sulphate filter paper, and sterile air is passed 

 through it to remove chloroform. For certain investigations it is then 

 necessary to add salt in sufficient quantity to restore the isotonicity of 

 the fluid. The period for which incubation and consequent auto-diges- 

 tion is allowed to proceed depends on whether the action of nucleo- 

 proteins or of the cytoplasmic radicals is to be studied. For special 

 researches, organs of embryos, which are devoid of acquired immunity, 

 are specially suited. 



Placental Culture Media.f — It has been shown that placental tissue 

 is exceedingly rich in the hydrolytic products of proteins, containing 

 large quantities of lysin, arginin, tryptophane, phenylalanine and allied 

 bodies. C. Wellmann has therefore made use of this material for the 

 cultivation of strictly parasitic and feebly saprophytic bacteria. Fresh 

 human placenta is thoroughly ground up in a meat chopper, after first 

 washing out the blood with sterile sahne. To each kilo of the macerated 

 placental tissue is added one litre of distilled water. The mixture is 

 allowed to infuse at refrigerator temperature for 48 hours, and is then 

 filtered through a Berkefeld N filter. The filtrate is tubed, or added to 

 2 p.c. melted agar and sloped. The medium is placed before using at 

 a temperature of 40° C. for two days to inactivate the contained 

 complement. 



Portable Incubator. | — jST. S. Ferry describes an incubator (figs. 103 

 and 104), which is useful when travelling, by means of which material 



* Centralbl. Bakt., Ite Abt. Orig., Ixv. (1012) pp. 412-15 (figs.). 



t Brit. Med. Jouru., 1912, i. pp. 1358-9. 



X Centralbl. Bakt., Ite Abt. Orig., Ixvi. (1912) pp. 142-3. 



