Until Folin devised his recent colorimetric method for quantitatively determining the uric acid of the blood, we were very much in the dark as to the actual amount of this substance in circulation. Abderhalden, in his text-book, states that the amount of uric acid in the blood is too minute for determination. The older methods, the cupric bisulphite method of Krüger and the silver nitrate method of Salkowski, are too crude and require too large an amount of blood for practical service. Folin hints that Garrod must have drawn considerably on his imagination in his "Thread" estimates, and expresses the opinion that practically all of the older statements in the literature as to the amount of uric acid in the blood, represent nothing more than guess-work.
This new method possesses two essentials: it is remarkably accurate and it requires comparatively small quantities of blood — from 15 to 25 grams.