and Laboratory Methods. 1425 



the corpuscles to a much greater extent. When these same substances in the 

 form of water solutions are mixed with the blood it is found that potassium 

 chloride and potassium sulphate are only taken up by the corpuscles when the 

 osmotic pressure of their solutions is higher than that of the serum. Magnesium 

 sulphate when in solution of lower osmotic pressure than the serum does not 

 enter the corpuscles. Ammonium chloride and sulphate in water solutions are 

 taken up by the corpuscles whether the solutions are hypertonic or hypotonic. 

 This method of the electrical conductivity gives excellent results in the measure- 

 ment of the permeability of the corpuscles for electrolytes, but is not so well 

 adapted for the treatment of the resorption of non-conductors, as for example, urea. 

 The last paper deals with the so called " demarcation current " of a resting 

 muscle which has been injured in some way. The sartorius muscle of the frog 

 was used and this was injured, either by wounding with a knife or by the appli- 

 cation of chemicals to its surface, or by both methods in combination. The 

 arrangement of the experiments was as follows : on the ends of two "normal," 

 unpolarisable electrodes filled with .In KCl were placed secondary electrodes, 

 one of which was filled with an indifferent fluid - .In NaCl - and the other with 

 the substance \vhose effect on the muscle was to be tested. On the ends of 

 these secondary electrodes the muscle from a curarised frog was laid. Before 

 beginning each experiment the muscle was tested and found to give no current. 

 From the primary electrodes wires were led to a suitable apparatus for measuring 

 the current. With such an arrangement it was found that distilled water in con- 

 tact with the surface of the muscle produces a negative electrical condition at 

 that point. After a short time ( fifteen to thirty minutes), however, this affected 

 area becomes positive with reference to the rest of the muscle, and later again 

 changes to negative. If very dilute solutions of KCl are brought in contact with 

 the muscle, analogous phenomena appear, the only difference being that in this 

 case the negative and positive phases of the current are of shorter duration than 

 when water is used. The sheath of the muscle fibril has an important influence 

 on the electromotive force of the muscle, the current becoming weaker as this 

 surface layer becomes more and more injured. The author believes that all 

 these phenomena can be brought into agreement with the laws of physical chem- 

 istry. It appears that the contractile substance and the sheath are affected sep- 

 arately by the irritating agent. In case of each there arise decomposition 

 products, whose positive ions move faster than their associated negative ions. 

 The diffusion of these ions is the primary cause of the electrical phenomena, and 

 the changes in the direction of the current are the results of changes in the 

 permeability of the sheath. This paper forms an important step towards the 

 bringing of animal electricity, one of the most peculiar of physiological 

 phenomena, under physical and chemical laws. r. p. 



Courtade, D. L'Irritabilite dans la Serie These two numbers in the " Scientia " 

 animale. Paris (Carre & Naud). Pp. 86, ^^^-^^ ^^^ ^^^j^j jj^^j^ hand-books on 



Bonnier, P. L'Orientation. Paris (Carre & their respective subjects. Their pur- 



p. 90, 1900. pose is not the publication of new facts 



or theories, but rather to give a clear, concise, and more or less elementary 



