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



the blood white ; but it would require to bo repeated several times to 

 enablo us to judge, whether the appearancos of the clot were really 

 due to the action of the alcohol, or wero owing to some accidental cir- 

 cumstance. 



Eggs. — On the 16th of October, U., after fasting sixteen hours, had six eggs for 

 dinner, which were eaten, as before, with a little salt and nothing else but water 

 for drink. He was bled immediately before the meal, and again four hours after 

 it. The scrum from the first bleeding was limpid, and, on supersaturating it 

 with salt, gave a true precipitate falling altogether to the bottom. The serum 

 from the second bleeding was whitish, and, on being treated in the same way, it 

 crave only a scanty precipitate, but a very abundant sublimate, which remained 

 swimming at the surface for many days thereafter. The coagulum of the blood 

 first drawn had a plentiful fibrinous crust, very transparent ; the other coagulum 

 was natural. 



This result corresponds with those obtained on two former occasions 

 mentioned above, when eggs had been eaten. The experiment was 

 repeated, for the purpose of confirming an argument which has been 

 employed above as to the source of the white matter of the serum. It 

 is obvious, that the meal of eggs either introduced into the blood a 

 sublimable substance not before present, or that it altered the quality 

 of some substance previously existent; which last is a less probable 

 supposition. The small quantity of the serum first obtained, prevented 

 any comparison of the relative quantities of the precipitates. 



The following conclusions may be deduced from the observations 

 and reasonings contained in this and the former memoir. 



1. The serum of the blood of a healthy man fasting, is perfectly 

 transparent, and of a yellowish or slightly greenish tint. 



2. A heterogeneous meal, such as that usually set on the tables of 

 the rich, renders the serum white. 



3. The whiteness may commence as early as half-an-hour after 

 eating, and may continue ten or twelve, and sometimes as long as 

 eighteen hours, according to the kind and quality of the food, and the 

 state of the functions of primary and secondary digestion. 



4. Starch, and Sugar, and probably all vegetable substances desti- 

 tute of oil, give no whiteness to the serum of the blood. 



5. Fibrin, Albumen, and Casein, and probably Protein-compounds in all 

 their forms if destitute of oil, give no whiteness. 



6. Oils combined, whether naturally or artificially, with protein- 

 compounds or with starch, render the serum of the blood white ; pro- 

 bably, therefore, oils produce that effect in whatever way taken. 



7. Gelatin seems to render the serum of the blood white ; this, 

 however, cannot be considered as certainly established, as there may 

 have been some fat in the beef-tea which was taken along with the 

 calf-foot jelly in both experiments on which the above conclusion rests. 



8. The coagulum of tho blood very frequently exhibits, after taking 

 food, a crust of pellucid fibrin, or of pellucid fibrin dotted with more 



