186 Proceedings of the Royal Society of Edinburgh. [Sess. 
VIII. — Clinical Methods of Estimation of Sugar in the Blood. 
By Dr Harry Rainy and Miss Christina M. Hawick, B.Sc. 
(MS. received March 18, 1916. Read May 1, 1916.) 
The variation in the sugar content of the blood in certain pathological 
conditions has created the need for modes of estimation which require only 
a small amount of blood and at the same time give sufficiently reliable 
results. The more recent methods of estimation fall under three types : 
(1) those in which the method of Rona and Michaelis for the precipitation 
of the protein is combined with Bertrand’s method for sugar estimation, 
(2) MacLean’s more recent method, and (3) the “ micro-method ” of 
Ivar Bang. 
Clinically, the third method possesses the great advantage that, as very 
little blood is required for an estimation, the observation can be repeated at 
short intervals during the day without incommoding the patient. In its 
original form it has several sources of error which prove a great drawback 
to its use, but by certain modifications these can be overcome. 
(1) a. Gardner and MacLean in 1914 published a method whereby blood 
sugar could be estimated, and in which 2 c.c. of blood were required. The 
blood is measured into a small mortar, treated with 7 c.c. of water, 14 c.c. of 
dialysed iron, and 1 c.c. of saturated sodium sulphate. The whole is stirred 
and the thick pasty mass squeezed through a cloth. The resulting some- 
what turbid fluid is filtered, and exactly 16 c.c. of the filtrate are used for a 
sugar estimation by Bertrand’s method. The cuprous oxide is filtered off 
through asbestos, washed with water, dissolved in Bertrand’s ferric 
sulphate solution, and the amount of sugar estimated in the ordinary way 
from the subsequent permanganate titration. 
b. In June 1915 Stein and Wiseley published a similar method in which 
*5 c.c. of blood is used. Into a centrifuge tube, accurately calibrated at 
the 0 - 5, 1, 5, and 10 c.c. points, are put a sodium fluoride solution to the 
0’5 c.c. mark, blood to the 1 c.c. mark, and water to the 5 c.c. mark. A 
pinch of Rochelle salt is then added, the whole shaken and allowed to 
stand until the Rochelle salt has dissolved. A 5 per cent, solution of 
dialysed iron is added up to the 10 c.c. mark, the tube corked, and the 
whole vigorously shaken and then centrifugalised for from 3 to 5 minutes. 
