Dr. Buchanan on the State of the Blood after taking Food. 65 



was produced. I tried also bicarbonate of soda, but with no better 

 success ; and my stock of serum being exhausted, I abandoned the 

 inquiry, but, as will be seen below, without losing sight of it 



Wjiite-Fibh.— On the 2d of June, IT., after fasting the usual time, had four pounds 

 of white-fish, of which he took a large proportion, with no other accompaniment 

 than a little salt. He was bled at two, and at four hours after the meal. Tin? scrum 

 on both occasions was scanty, obviously owing to air-bells on the coagulum, which 

 had caused it to adhere to the edge of the cup almost all round. The coagulum 

 was red on the surface, and very loose in texture from retained scrum. The scrum 

 in both cups was quite transparent, and on being supersaturated with salt, gave a 

 voluminous precipitate like that from milk already described. 



These two last experiments fully satisfied me, that partaking freely 

 of a highly azotized diet does not necessarily occasion any milkiness 

 in the serum of the blood. It appeared to me, however, probable, that 

 tho white matter which in these instances was precipitated by the salt, 

 was the very same that in other circumstances causes the serum to bo 

 milky, the only difference being, that in the former instances the white 

 matter is completely dissolved, and in the latter only imperfectly. 

 Now, in the experiment made on the 12th of April, a man fed on 

 arrow -root was found to have the serum of his blood transparent, or 

 without whiteness, and no farther examination of its qualities was 

 made except ascertaining that it was fermentable on the addition of 

 yeast. But it was desirable to know whether a diet of Starch, although 

 it did not render the serum of the blood milky, might not, as in the 

 cases just detailed, introduce with it a white matter precipi table by 

 salt 



Arrow-Root. — Accordingly on the 15th of June, M., after fasting the usual time, 

 had a meal of arrow-root, prepared with water, and seasoned with spice. He took 

 it readily, but not so much of it as was taken on the last occasion. He was bled 

 at two, and four hours after the meal. 



Tho serum on both occasions was transparent, and with a greenish tinge. That 

 from the blood last drawn gave a precipitate with salt, but not so abundnnt as in 

 several former cases. The other specimen gave a much more abundant precipitate, 

 in part rising to the surface. This last also, on being filtered, left oily stains upon 

 the filtering paper, as I have since found the serum of the blood very frequently do. 

 I found the white precipitate from salt to be completely resoluble on adding as 

 much water as brings the solution somewhat under the point of saturation. On 

 again saturating with salt, the precipitate falls, and on again adding water, it is 

 redissolved, and so for several times in succession. 



Does, then, Starch give a white precipitate with salt like the azotized 

 principles? Before drawing this conclusion there are some causes of 

 fallacy to be guarded against. The white matter may have proceeded 

 from food taken before the fast, and the more abundant precipitate in 

 the blood first drawn seemed to countenance this conjecture. The 

 fast may not have boen strictly observed. Both these sources of error 

 will be procluded by drawing a little blood before the meal, and test- 

 ing tho serum with salt. Lastly, arrow-root contains a certain pro- 

 portion of azotized matter, which, in some specimens examined by 



