ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 7:21 



number of bacteria in a culture whicb were no longer capable of develop- 

 ment was easily determined. 



Method for Distinguishing between different Kinds of Blood. * — 

 Dr. Ublenbutb's method promises to fill up a gap which has long been 

 vacant in the technique of forensic medicine. Before dealing with 

 human blood, the author experimented with the blood of cattle. At 

 intervals of 6-8 days he injected 10 ccm. of defibrinated ox-blood into 

 the peritoneal sac of rabbits — five times in all. Eighteen different blood- 

 solutions were then tested in the following way : — The blood was diluted 

 with water until the fluid was of a faint red hue (about 1 p.c). The 

 solution was filtered, and the filtrate mixed with an equal bulk of 1 * 6 per 

 cent, salt solution. The accurate admixture is of great importance. 



To about 2 ccm. of this blood-solution 6-8 drops of the serum of a 

 rabbit previously treated with ox-blood were added. In such solutions 

 au obvious and increasing cloudiness arose. All other blood solutions 

 remained clear, as did also the untreated normal rabbit's blood. 



The method was then extended to human blood. Eabbits were in- 

 jected with human blood. A turbidity arose only in those solutions to 

 which human blood was added. Only a trace of blood was necessary to 

 bring about the reaction, and blood which had been dried on a board for 

 four weeks produced a positive result. 



Piorkowski's Method of Detecting Typhoid Bacilli.f — A. Peppier 

 carefully tested Piorkowski's method for demonstrating the presence of 

 typhoid bacilli, and arrived at the conclusion that, though of considerable 

 merit, it was not always satisfactory ; for a negative result does not dis- 

 prove the presence of typhoid ; and even if the colonies appear charac- 

 teristic, there is no certainty that they may not be those of some other 

 bacterium, so that further tests are necessary. 



In the course of the investigation, a new bacterium, designated Bac- 

 terium alcalifaciens, was isolated by means of phenolphthalein-urine- 

 gelatin, and this organism was employed to render urine alkaline in the 

 preparation of the urine-gelatin. 



Acid-free Cement.j — 250 grin, of powdered dammar resin are dis- 

 solved in 1 litre of petroleum ether in a spacious flask, and then £ litre 

 of 10 p.c. NaHO are added. The mixture is well shaken and boiled 

 for 10 minutes, and then, after having been allowed to settle, the perfectly 

 acid-free ethereal solution is filtered off. 



Iron and Phosphorus. § — J. E. Stead gives parts iii. and iv. of his 

 researches. Part iii. deals with the constitution and microstructure of 

 pig metals containing iron, carbon, and phosphorus. The author arrives 

 lit the following conclusions (inter alia) : — (1) That with the aid of the 

 Microscope it is possible to detect the phosphide eutectic in pig irons, 

 even when the amount is as low as 0*03 per cent. ; (2) that in white 

 irons it is necessary to use the heat-tinting process to enable the cementite 

 to be distinguished from the phosphide. 



Part iv. deals with the diffusion of phosphide of iron in iron, and 



* Deutsche Med. Wochenschr., xxvii. (1901) pp. 82-3. 



t Inaug. Diss. Erlangen, 1901, 8vo, 77 pp. See Centralbl. Bakt., V Abt., xxix. 

 (1901) pp. 879-81 ; Bot. Centrabl., lxxxvi. (1901) pp. 182-3. Cf. this Journal, 1900, 

 p. 639. t Zeitschr. angew. Mikr., vii. (1901) p. 102. 



§ Metallographist, 1901, pp. 332-60 (2 figs.). Cf. this Journal, ante, p. 608. 



