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



labouring under some diseaso for which he had been put upon an 

 antiphlogistic rogimon — and lastly, with that obtained from an animal 

 kept long without food. 



The first method being that most readily put in practice, was tried 

 first. As a twenty-hour hour's fast is attended at least with eight hours 

 of uneasy sensation, it could not be expected, unless enforced, to be 

 rigidly performed but by a person interested in the success of the 

 experiment. It was also desirable that the person experimented upon 

 should not be under confinement, but take as much exercise as possible 

 to promote the assimilative actions of the system. I therefore tried 

 this experiment upon myself. 



Arrow-Root. — I dined lightly between four and five o'clock in the afternoon ot 

 the 25th of July ; in the evening I took exercise on horseback, and next day went 

 about my usual avocations with a good deal of walking, till between five and six in 

 the afternoon, having taken nothing in the interval but a draught of water before 

 going to bed. I now had blood drawn from the arm by a medical friend, and 

 thinking the opportunity a favourable one for trying the effect of starch, I dined 

 upon arrow-root, prepared with water and sweetened with sugar, of which I took 

 a large bowlful — in appearance a mess for a ploughman, but which in reality con- 

 tained no more than three ounces of dry arrow-root powder. I also drank freely of 

 water sweetened with sugar, and was bled again three hours after the meal. 



The serum from both bleedings was quite limpid, and of a deep amber yellow. 

 That from the first bleeding had the deepest tinge ; on supersaturating it with salt it 

 became slightly troubled, but without losing its transparency, and at length showed 

 pale flocks, which became whiter in colour as they subsided to the bottom. The 

 serum from the second bleeding gave a precipitate, which was likewise flocculcnt, 

 of a more decidedly white colour, and more abundant, although very insignificant 

 in point of quantity when compared with the precipitates obtained after a full 

 azotized meal. 



This experiment shows, that abstinence from food for twenty-four 

 hours, by a person in good health, taking active exercise in the open 

 air, reduces to a minimum, but does not altogether remove the precipi- 

 table matter of the blood. The two other experiments suggested above, 

 lead to the same conclusion ; and the last further shows, that a very 

 prolonged fast introduces a new complication into the question by 

 occasioning an incipient decomposition of the blood. 



In the beginning of August I got from a medical friend some serum from the blood 

 of a man bled for a pleurisy, of which he died soon afterwards. It gave a scanty 

 precipitate on being saturated with salt. 



On the 1 6th of August, a dog, which had been kept fifty-one hours without food, and 

 had drunk little although allowed a free supply of water, was bled from the saphena, 

 to the extent of about two ounces. The blood trickled slowly down the leg, and 

 was coagulated in part before the whole had been received in the cup. Whether 

 owing to this circumstance, or to the long fast, the serum was tinged deeply red, 

 apparently from the colouring matter being dissolved, for it was quite transparent, 

 and did not lose the colour by standing at rest. Salt gave a precipitate, although 

 little abundant. 



We may infer then from these experiments, that it is not possible, 

 without carrying fasting to a greater length than prudence or humanity 



