August 9, 1907] 



SCIENCE 



175 



theory, based upon the ionization constant of 

 carbonic acid (3 X 10"') and of the ion 

 H,PO, (2X10-')- Althougb the equilibrium 

 in such a system at 40° C. may be somewhat 

 different, it is evident that this equilibrium 

 will almost perfectly protect protoplasm from 

 variation in neutrality. The variation in 

 hydrogen and hydroxyl ionization can hardly 

 be more than 5 X 10"'. 



The Influence of Adrenalin upon the Venous 

 Blood Flow: Eussell Burton-Opitz. 

 The blood flow in the femoral, external jug- 

 ular and azygos veins was measured by means 

 of the stromuhr previously described by the 

 author. During the experiment, solutions of 

 adrenalin were injected centrally to the stro- 

 muhr. The effect of the adrenalin showed it- 

 self in a retardation of the venous inflow, 

 which appeared in from fourteen to sixteen 

 seconds after the injection. Considering the 

 velocity of the venous blood stream, it must be 

 assumed that the adrenalin did not produce its 

 characteristic effect until it had reached the 

 arterial side of the circulatory system. The 

 experiments tend to disprove the existence of 

 vaso-motor nerves in tha central veins and the 

 pulmonary circuit. 



The Viscosity of Laked Blood: Eussell Bur- 

 ton-Opitz. 



It was found that the viscosity of laked 

 blood prepared by the process of freezing is 

 very much less than the viscosity of defibrin- 

 ated blood. The specific gravity was only 

 slightly lessened. Examples of the experi- 

 mental data are appended: 



Defibrinated Blood 



Spec. Gray. Viscosity 



1.0566 665.74 



Laked Blood 

 Spec. Gray. Viscosity 

 1.0563 982.35 



The Determination of Ammonia and Urea in 

 Blood: W. McKiM Marriott and C. G. L. 

 Wolf. 



Ammonia is determined by distillation in 

 vacuo. 100 c.c. of blood are treated with 50 

 c.e. of saturated sodium chlorid solution, and 

 250 c.c. of methyl alcohol are added to the 

 mixture. The resultant precipitate is finely 

 granular. The residue is filtered off in a filter 

 press, and the filtrate distilled for forty min- 

 utes, with the temperature of the water bath 



at 40-50° C. The receivers are charged with 

 n/oO sulphuric acid, and the acid titrated with 

 ji./50 sodium hydroxid free from carbonate. 

 Sodium alizarin sulphonate is used as the in- 

 dicator. The results are perfectly accurate. 



The residue after distillation is made acid 

 with hydrochloric acid, evaporated and hy- 

 drolyzed with 10 grams of glacial phosphoric 

 acid at 150° C The ammonia formed from 

 the urea is then distilled into n/50 acid. The 

 duplicates have shown very satisfactory agree- 

 ment, but it is quite certain that not all the 

 urea which is added to a sample of blood is 

 recovered. It is probable that the carbohy- 

 drates in the residue combine with the urea 

 at the temperature of hydrolysis and prevent 

 the formation of ammonia. 



The Resolution of Fihrinous Exudates, with 



Exhibition of Specimens : Eugene L. Opie. 



During the early stage of inflammation, a 

 fibrinous exudate, freed from the serum by 

 washing in salt solution, undergoes digestion 

 when suspended in an alkaline (0.2 per cent, 

 sodium carbonate), or in an acid, medium 

 (0.2 per cent, acetic acid). At the end of six 

 days, when fluid has disappeared from the 

 pleural cavity, digestion fails to occur in an 

 alkaline medium, but occurs with great ac- 

 tivity in the presence of acid. 



During the first stage of the inflammatory 

 reaction, when fluid is abundant and the fibrin 

 which is present digests in the presence of 

 alkali, polynuclear leucocytes are very numer- 

 ous in the meshes of the fibrin. In the second 

 stage, when fluid has in great part disappeared, 

 and the fibrin contains only one enzyme active 

 in the presence of acid, polynuclear leucocytes 

 have disappeared and only mononuclear cells 

 are embedded in the fibrin. 



Since the acids, which, in vitro, favor the 

 action of the enzyme present in the second 

 stage of the process, do not occur in the body, 

 the possibility has suggested itself that carbon 

 dioxide brings this enzyme into action. When 

 carbon dioxide is passed through normal salt 

 solution in which strips of such fibrin are sus- 

 pended, digestion is very greatly hastened. 

 The normal inliibition exerted by blood serum 

 upon the enzjTne is overcome by carbon diox- 



