514 SUMMARY OF CURRENT RESEARCHES RELATING TO 



acid for 5-7 minutes. They were then washed in water, and afterwards 

 transferred to the following staining solution : anilin-blue ' 5 grin., 

 orange G 0*2 grin., oxalic acid 2*0 grm., distilled water 100 c.cm. 

 After 20 minutes or so the sections were washed quickly in water, de- 

 hydrated in alcohol, differentiated with a couple of drops of anilin oil, 

 cleared up in xylol, and mounted in balsam. 



Staining Capsules of Pneumococcus and Streptococcus.* — P. H. 

 Hiss, jun., uses a half saturated aqueous solution of gentian-violet. 

 Air-dried and heat- fixed films are stained for a few seconds with the 

 solution. Water must not be used in making the films, but serum, or 

 some similar fluid. After staining, the dye is washed off with 0"25 p.c. 

 potassium carbonate solution, and the film examined in this fluid. 



Another method is to treat the film with a 5 or 10 p.c. solution of 

 gentian-violet or fuchsin (5 c.cm. saturated alcoholic solution to 95 c.cm. 

 H 2 0). Heat to vaporisation, and wash off with 20 p.c. solution of copper 

 sulphate. Dry, and mount in balsam. 



The author confirms the observations of Ortmann (1888) and others 

 that pneumococcus regularly develops capsules when cultivated in blood 

 serum. From his own experience he finds that one of the most favour- 

 able media for the development of capsules consists of 1 p.c. starch- 

 bouillon and serum (serum 1 part, bouillon plus 1 p.c. starch 2 parts), 

 and sterilised at 65°-70°. 



Metallography, etc. 



Influence of Velocity on the Law of Deformation of Metals.f — 

 The pressures developed by explosives in guns are measured by the 

 compression of small copper cylinders placed in crusher gauges. The 

 accuracy of the measurement depends on the calculation of the pressure 

 corresponding to a definite compression. The stress-strain relation for 

 the cylinders is determined by submitting them to definite pressures 

 applied much more slowly than under ballistic conditions, and measuring 

 the compression. It has been established that the resistance of a rapidly 

 compressed cylinder is greater than that of a cylinder slowly compressed 

 to the same form. P. Yieille and R. Liouville point out that the 

 resistance cannot be calculated from the amount and velocity of com- 

 pression. Two cases are to be considered : (1) the measurement of 

 maximum pressure ; (2) the determination of the law of increase of 

 pressure. The errors appear to be much greater for (2) than for (1). 

 The authors promise an account of their work on the subject. 



The Equilibrium Curves of the System Iron and Carbon .} — 

 H. v. Jiiptner reviews the determinations of freezing point curves made 

 by Mannesmann and Osmond, Roberts- Austen, Carpenter and Keeling, 

 and Wiist. Selecting those points which appear to be the most trust- 

 worthy, the author has plotted a diagram showing the probable equi- 



* Joum. Exper. Med., vi. (1905) pp. 317-45 (12 figs.). 



t Comptes Rendus, cxlii. (1906) pp. 1057-8. 



j Iron and Steel Mag., xi. (1906) pp. 377-82 (1 fig.). 



