412 SUMMARY OF CURRENT BESEARCHES RELATING TO 



downwards. In old cultures, where the upper portion of the agar has 

 adhered to the tube, the medium can be loosened with a suitable spatula. 

 The above method applies to agar and serum agar cultures (which 

 do not stick to the tube). With gelatin cultures the test-tube should be 

 held in warm water until the layer next the glass becomes melted. If 

 the tube is then held steeply the culture column will often glide out 

 into the Petri dish without further manipulation. 



Demonstration of Streptococci in the Plowing Blood.* — S. Reich- 

 stein draws attention to the fact that bacteriological investigation in 

 cases of septicaemia is often unsatisfactory, and suggests modifications 

 in technique in order to bring about better results. His investigations 

 were carried out on rabbits infected with Streptococcus pyogenes. The 

 bleedings were made by means of aspiration of the jugular vein, which 

 vein presents advantages over (1) the marginal vein of the ear, as the 

 blood can be procured sterile and without producing thrombosis ; and 

 (2) the carotid artery, as repeated samples can be taken for purposes of 

 continued research. The use of a medium-sized syringe is insisted on, 

 as in the filling of a large syringe coagulation of the blood may take 

 place. Samples of blood taken at varying periods were defibrinated or 

 treated with oxalate solution or leech extract to prevent coagulation. 

 The first method gave poor results on account of the organisms becoming 

 entangled in the fibrin clot ; the other methods, however, gave satis- 

 factory counts on plating out. The blood samples were inoculated on 

 to the surface of glycerin-agar, glucose-agar, and ascitic-fluid agar 

 respectively, but no significant variation in the number of the resulting 

 colonies was observed. Blood samples should be placed for twenty -four 

 hours in the incubator previous to plating ; if left at room-temperature 

 the contained organisms may decrease in numbers or perhaps die out 

 completely. 



(3) Cutting 1 , including: Embedding- and Microtomes. 



Paraffin Ribbon-carrier. f — The carrier described by Robert T. Hance 

 was designed to handle the paraffin ribbon as it comes from the micro- 

 tome in such a way as to preserve a perfect series and to eliminate some 

 of the difficulties encountered with the usual method. Not only is the 

 old method of cutting long serial sections into short pieces and laying 

 them upon a sheet of paper tedious, but the danger of losing a part of 

 the sections in a sudden draught or having them hopelessly mixed is 

 great. Without careful shielding, ribbons placed upon paper may not 

 be allowed to lie for any length of time before mounting. With the use 

 of the carrier long unbroken series may be wound on the drum and 

 allowed to remain until used. The writer lias allowed a ribbon to remain 

 on the earner for three days, exposed to all the draughts common in the 

 average room, and at the end of the time was able to mount a perfect 

 series with no difficulty. The inclined plane shown in the photograph 



* Centralbl. Bakt., lte Abt. Orig., lxxiii. (1914) pp. 209-23. 

 t Trans. Amer. Micr. Soc, xxxii. (1913) pp. 297-9 (2 pis.). 



