66 PHILOSOPHICAL TRANSACTIONS. [ANNO 17 Q6. 



the urine, and caused an inability to void it without assistance, till the coagulum 

 was dissolved. With a view to ascertain how far this had been the case, and dis- 

 cover what changes the blood undergoes when placed in such circumstances, I in- 

 stituted the following experiments. They were performed by Mr. Charles Grover, 

 a very ingenious surgeon, at present house surgeon in St. George's hospital. 



Exper. 1. 4 oz. of blood were drawn from the arm into a phial containing 4 oz. 

 of fresh urine, and the phial was kept in the temperature of the human body; in 

 15 minutes the whole mixture formed a uniform firm coagulum, and appeared 

 wholly composed of blood. This experiment was made to ascertain the probable 

 time the blood would take to coagulate in the bladder. 



Exper. 2. 6oz. of blood were drawn from the arm into 6oz. of fresh urine; in 

 15 minutes the whole mass became one solid coagulum. In 7 hours, 6 drs. of 

 clear fluid were separated from it; this was poured off, and the same quantity of 

 fresh urine was added; after standing 9 hours it was poured off; some red globules 

 were mixed with it, but sunk to the bottom undissolved. The coagulum had fresh 

 urine added to it 3 times a day, the former urine being previously poured off, and 

 allowed to stand some hours for examination. For the first 5 days the coagulum 

 appeared to undergo little change, except becoming smaller in size, and the urine 

 poured off from it was tolerably clear, but on standing deposited a dark cloudy se- 

 diment. On the 6th day, the urine, when poured off from the coagulum, was of 

 a dark red colour, and deposited a greater quantity of a dark coloured sediment, 

 but on standing became tolerably clear. On the 9th day, the coagulum was re- 

 duced to the size of the original quantity of blood drawn from the arm. On the 

 13th day, the size of the coagulum was a good deal reduced; the urine poured off 

 from it was still more tinged with the red globules; but when allowed to stand, the 

 upper part became clear, and free from the red tinge, and the sediment had the ap- 

 pearance of a whitish powder. From this time the quantity of white sediment in- 

 creased, and the size of the coagulum diminished. In its decrease from this period 

 the loss was from its external surface, and nearly equally all round; what remained 

 appearing like the nucleus of the original coagulum. On the 25th day, it was of 

 the size of a large cherry, and on the 29th it entirely disappeared. Some red 

 globules were very distinctly seen in the sediment along with the white powder. To 

 see how far the changes the blood had undergone in this experiment depended on 

 the peculiar properties of the urine, the following experiment was made, with blood 

 and common water. 



Exper. 3. 6 oz. of blood were drawn from the arm into 6oz. of water. In a 

 -j- of an hour, the whole became one solid coagulum. In 12 hours, 6 oz. of a 

 clear water, of a bright red colour, were separated, nor did it on standing deposit 

 any sediment. This coagulum had fresh water added to it twice a day, and what 

 was poured off was allowed to stand for examination. The coagulum on the 2d 

 day began to break; on the 5th had a putrid smell; and in 18 days was almost en- 

 tirely dissolved. The water poured off was of a bright red colour from the be- 



