Dk. Buchanan an the White or Opaque Serum of the Blood. 235 



mediately charred, and burned away almost completely. Dr. R. D. Thorn- 

 son was kind enough to examine a specimen of it for me, but it was too 

 minute in quantity to admit of a satisfactory analysis. He found it 

 quite insoluble in ether and alcohol, while it dissolved in caustic pot- 

 ash. On boiling it in a solution of sugar of lead, it gave traces of 

 black sulphuret. He concluded, tlierefore, that it contained no fixed 

 oil, and consisted most probably of a protein compound^ like albumen 

 or fibrin. 



A further opportunity was afforded of examining the chemical quali- 

 ties of this kind of serum in some specimens obtained for illustration, 

 with the prospect of submitting this subject to the consideration of the 

 Society. 



A man about thirty years of age, after fasting eighteen hours, dined 

 upon twenty -four oz. of a pudding, consisting of two parts wheaten flour, 

 and one part suet, seasoned with salt. Two oz. of blood taken before the 

 meal, yielded a perfectly limpid serum. Seven ounces were taken 

 three hours after the meal, and the same quantity six hours after it. 

 The serum from the former was like syrup, but a little white ; that 

 from the latter was milk-white. The white matter in the latter was 

 separated by Dr. Thomson, by means of salt and the filter, and ap- 

 peared similar to the substance he had before examined. It contained 

 no fixed oil. The other specimen of serum threw up its cream spon- 

 taneously. It left upon the filter only a trace of white matter, but a 

 notable proportion of a fixed oil, which was easily demonstrated, by 

 merely drying the filtering paper, and holding it between the eye and 

 the light. It can scarcely be doubted that this oil was derived from 

 the suet of the pudding, while the white proteinaceous substance most 

 probably represented the gluten of the flour. Thus two of the three 

 elements of which the food consisted, were found in the blood, but the 

 starch, the most abundant of all, was sought for in vain. 



Postcript. After the meeting of the Society on the evening of the 

 13th inst , it occurred to me as possible, that the starch might be con- 

 verted by the organs of digestion into sugar, and be absorbed in that 

 form into the blood. I accordingly procured some yeast next day, 

 and treated with it the serum of the blood, which had been taken three 

 hours after the meal, proceeding in the same way in which I am in 

 the habit of examining diabetic urine. Fermentation ensued, and con- 

 tinued about forty-eight hours, the heat not having been regularly 

 maintained. The serum from the blood of another individual who 

 had used the same diet, but more sparingly, was treated in the same 

 manner, when the same result ensued, only the gas was somewhat more 

 abundant. But what struck me as more remarkable still, was, that 

 the serum of the blood which had been taken from both these indi- 

 viduals after fasting, likewise fermented ; although the quantity of 

 gas obtained was much less than in the former instances. I found 

 that the largest quantity of gas obtained in these experiments was 



