384 



Prof. W. M. Bayliss. 



chloride is finally added. For clinical use, sterilisation by heat does not 

 perceptibly diminish the viscosity. The mucilage of the British 

 Pharmacopoeia, when diluted by adding 400 c.c. of water to 100 c.c, makes 

 a 7-per-cent. solution. 



Finally, gelatin is very convenient in many ways, as solutions are quickly 

 made. If the maximum viscosity is required, a temperature above 40° C 

 should not be employed in making the solution. If heated to 100°, as 

 Moore and Eoaf (4) showed, the osmotic pressure rises. The decrease of 

 viscosity on heating is a disadvantage for clinical use, since sterilisation is 

 indispensable, owing to the usual presence of micro-organisms, especially 

 those of tetanus. 



The Table below gives numerical data of the properties of various 

 solutions, so far as they concern us here. 



Table II. 



Viscosity 

 (H 2 = 1). 



Viscosity in 

 dynes x 10 3 

 (H 2 = 6'6). 



Osmotic^ 



pressure 

 against water. 



Osmotic 

 pressure against 

 Ringer solution. 



Blood of cat 



Ox serum 



Soluble starch (Kalilbaum) 



4 per cent. 

 Soluble starch (Kahlbaum) 



4 per cent., after cold 



storage 



Wheat starch, 2 per cent. .:. 

 Amylopectin, 1'72 per cent. 

 Gum acacia, 7 per cent., 

 Ca salt 



Gum acaciaj 7 per cent., 



Na salt 



Gelatin, 6 per cent 



Gelatin, 6 per cent., after 



heating to 100° 



3-0 

 1-5 



1- 7 



2- 26 



2- 65 

 4-8 



3- 1 



3-4 



4 

 3 



19 -8 

 9-9 

 11-2 



16 



17 -5 

 32 

 20 -5 



22 -5 



26 -4 

 19 -8 



mm. Hg 

 116 



218 

 95 



mm. Hg. 



36-40 

 14-16 



39 



38 -5 

 63 



Although some of these figures are to be found in the literature, I thought 

 it better to determine them all with the solutions actually used in my 

 experiments, and under similar conditions at 38°. Many of the data are 

 new. Others differ somewhat from previous determinations, as would be 

 expected from the variability of colloidal substances. 



In experimental test, it was found that injection of Singer's solution con- 

 taining one or more of these substances in sufficient quantity to raise the 

 viscosity to that of blood, even when iujected only in amount equal to that 

 of the blood lost, brought back the arterial pressure to its original height, 



