848 



SCIENCE. 



[N. S. Vol. XXIII. No. I 



On the Dicrotic Elevation at Different Points 

 of the Arterial Tree. — A preliminary com- 

 munication: Percy M. Dawson. (Pre- 

 sented by J. E. Murlin.) 

 The author has observed considerable local 

 variation of the dicrotic elevation in many 

 arterifes in dogs. The pulse wave was studied 

 by means of the Hiirthle manometer. The ob- 

 servations were made on numerous arteries. 

 A satisfactory explanation of the local varia- 

 tions observed will be sought through further 

 experimentation. 



The Influence of Suhcutaneous Injections of 

 Dextrose upon Nitrogenous Metabolism: 

 Frank P. Underhill and Oliver E. Clos- 



SON. 



In experiments with glucose similar to those 

 described by Scott the authors confirmed his 

 observation that nitrogenous metabolism is in- 

 creased and a greater excretion of oxalic acid 

 results. In no case, however, was there observed 

 a significant change in the proportion of the 

 various forms of excreted nitrogen. The in- 

 creased proportion of ammonia in the urines of 

 Scott's dogs is attributed by the authors to the 

 fact that most of the animals were suffering 

 from severe cystitis due to catheterization. The 

 authors conclude that subcutaneous injections 

 of large quantities of glucose do not give any 

 evidence .of toxic action and they suggest that 

 such injections of glucose may be useful as a 

 method of parenteral feeding, since quantities 

 equal to seven grams per kilo may be thus ad- 

 ministered to dogs and rabbits without elimi- 

 nation in the urines of more than mere traces 

 of the sugar. 



Diffusion into Colloids and a Biological 

 Method for Testing the Bate of Diffusion: 

 RiwoN Flexner and Hideyo Noguchi. 

 The experiments summarized in this report 

 were made with hemolytic substances sus- 

 pended in isotonic saline solution and in agar- 

 agar and gelatine jelly. The rate of diffusion 

 could be measured by the depth and degree of 

 hemolysis produced in a jelly containing in 

 suspension susceptible red blood corpuscles. 

 The experiments were varied : the red corpus- 

 cles were suspended in the warm jelly, which 

 was permitted to congeal. The blood jelly 



was overlaid with the hemolyzing agent dis- 

 solved in saline solution or this agent was also 

 contained within a solidified jelly. The 

 hemolyzer was made to diffuse both down- 

 wards and upwards, according as the blood- or 

 hemolyzer-jelly was above or below. More- 

 over, the hemolyzer was placed in the jelly and 

 made to diffuse upwards into a watery solu- 

 tion, the amount of diffusion being measured 

 by the degree of hemolysis caused by the fluid 

 removed at given intervals. Two factors were 

 always considered: extent or degree of hemol- 

 ysis, and time. 



Acids, alkalies, salts, glucosides and toxine 

 diffuse into 0.9-per-cent. watery NaCl solution 

 more quickly than into a similar solution con- 

 taining agar-agar and gelatine. This reduc- 

 tion in rapidity of diffusion increases with 

 increase in concentration of the jelly. Ten- 

 per-eent. gelatine exerts a greater inhibition 

 than 2-per-cent. agar-agar, and 25-per-cent. 

 gelatine exerts greater restraint than 10-per- 

 cent, gelatine. The ratio between the rate of 

 diffusion and the concentration of the colloidal 

 suspension is, in the case of gelatine, nearly 

 inversely proportional to the square root of 

 the concentration of the colloid. In the case 

 of agar-agar, with which the possibility of 

 varying the concentration is far less than with 

 gelatine, the inhibitory influence is less 

 marked and does not conform to this rule. 

 Voigtlander's results are applicable to the 

 special case of agar-agar jelly. 



The influence of colloids upon the injurious 

 effects produced by bile salts upon the pan- 

 creas is due, apparently, to a modification by 

 reduction of the diffusibility of the bile salts, 

 which result diminishes the concentration of 

 the salts brought in contact with the pancreatic 

 tissues in a unit of time. 



William J. Gies, 



Secretary. 



THE AMERICAN CHEMICAL SOCIETY. 

 NEW YORK SECTION. 



The seventh regular meeting of the season 

 was held at the Chemists' Club on Friday, 

 April 6, at 8:40 p.m., Chairman Dr. F. D. 

 Dodge presiding. The following papers were 

 presented : 



