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



Gelatin. — On the 2d of April, 1844, two stout men (to distinguish whom I shall 

 employ the letters A. and B., as I shall employ other letters in the same way here- 

 after,) after fasting sixteen hours, had each for dinner two English pints of strong 

 beef tea, (veal soup was intended, but could not be had,) and half-a-crown's worth 

 of calf-foot jelly, being about the same measure of jelly. Each of them lost a few 

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



The serum of the blood first drawn from A. was opaline, but translucent ; and 

 exhibited nothing remarkable under the microscope. That of the blood last drawn 

 was very milky, being so opaque that the brightest light could not pass through it ; 

 and under the microscope it showed innumerable very minute amorphous particles, 

 almost none of them being spherical. The coagulum of this blood was natural, 

 while that of the former was mottled, but without any translucent crust, the mottling 

 being as if from the intermixture of florid and black blood. 



The scrum of the other man's blood was much more abundant. That from the 

 first bleeding was opaline, but less so than the corresponding serum of A. That 

 from the second bleeding was more opaline, but still translucent in a good light. 

 The coagulum of the latter was natural, while that of the former had a well- 

 marked crust of transparent fibrin. 



Common salt was found to separate a white cream not only from the milky 

 serum, (A. at six hours ;) but likewise from the three opaline specimens — of which 

 the explanation will be found below. 



These observations aro alluded to in the last memoir, having been 

 made immediately after it was submitted to the Society, but before 

 it was printed. The conclusions to which they appeared to lead, when 

 taken in connexion with the other observations there narrated, were, 

 first, that the azotized articles of food, after being digested in the first 

 passages, and absorbed into the blood-vessels, were found there, in the 

 first instance, as the white substance which gives to the serum of the 

 blood its milky colour; second, that oily substances appeared to con- 

 tribute to the formation of the white matter; and, third, that most of 

 the other non-azotized articles of food probably existed in the blood 

 in the form of sugar. These conclusions were not, indeed, formally 

 stated, because they were by no means established, and will indeed be 

 shown below to be to a certain extent incorrect; but I mention them 

 hero, as they give the clue to the experiments now to be described, 

 which were undertaken with the view either of confirming or over- 

 turning the hypotheses just stated. 



The object of the first trial was to determine whether Starch — a 

 non-azotized substance — made the serum white, and whether the 

 serum was fermentable. Arrow-root was selected as one of the purest 

 forms of starch ; and as the conditions to be fulfilled forbade its being 

 sweetened with sugar in the usual way, it was seasoned with aromatics 

 to correct its insipidity. 



Arrow -Root.— On the 12th of April, C, after fasting sixteen hours, had for 

 dinner arrow-root, made with water, and seasoned with mace and nutmeg. He took 

 from half-a-pound to a pound of it. He was bled at three and at six hours after the 

 meal. The serum in both instances was quite transparent, without any white matter. 

 The coagulum at three hours had a thick translucent fibrinous crust, marked with 

 numerous red dots : that at six hours was natural. This man did not feel again 



