J.F. Williams
1846 The Lancet  
SiR,—I regret that circumstances have prevented me from replying ere this to the letter of your correspondent" ″ MEDICUS," (THE LANCET, p. 53,) in which he seeks to know the evidence, and the value of the evidence, which may be furnished by a microscopic examination of dead and living blood. But before I proceed to this, let me dispossess your correspondent of the error which he entertains, when he says that I asserted, " that the spots of dried blood on the jacket of the accused must have
more » ... used must have flowed from a living person, and could not possibly (as the prisoner declared) have escaped from a dead body, because the blood corpuscles were imbedded in coagulated fibrine, whereas, immediately after death, the globules always separate from the fibrine, the latter coagulating into a mass in which no blood-globules remain." Now I need not say that such considerations as these I never had anything whatever to do with; they are not facts, and they would have proved me hasty and grossly ignorant if I had ever entertained them. Let me, however, refer to the manner in which I conducted the inquiry, so as to point out the value of the evidence which I obtained from it, and the mode in which I reasoned upon that evidence. A jacket and waistcoat were placed in my hands for examination. After a careful inspection, I discovered that the left sleeve of the one was marked by a large blood-patch, and that ' , there were many blood-spots upon other parts of both the garments; several of these spots had an oblique inclination,and appeared to have come from a jet. I then removed a portion from a great many of the spots, and examined them successively under the microscope; by this means I detected the blood-corpuscle, the fibrin-coagulum, the fatty scalp-epithelium, and a portion of brown hair; after this, other portions of the spots were placed in a test tube, with water, and when examined chmically thev gave the follnwing' results:— 1. The solution had a pink-colour, and small coagula of fibrin were diffused through it. 2. The addition of acid or alkali merely browned it; the pink-colour was not heightened or rendered green. 3. Strong nitric acid produced flocculi of albumen. 4. Bichloride of mercury did the same. 5. Heat also coagulated the albumen and rendered the solution turbid. The day after this inquiry, the police-sergeant brought me a piece of matting which was marked with a large blood-stain. The microscope demonstrated the presence of blood-corpuscles, and scalp-epithelia, but there was no evidence whatever of the existence of fibrin in it. A chemical examination also gave the same results as the preceding, excepting that the solution was not turbid from the presence of coaguled fibrin. I Two days after this, a police constable brought me a piece of wood, part of the beading from the window; it appeared to be stained by blood from a hand, for there were the markings of the skin rugae upon it: when this was examined by means of the microscope, I could only detect a sort of granular dust, there were no blood-corpuscles, or fibrin, or epithelia, in it; and when a little of it was scraped into water, the red colouring matter soon subsided, leaving the superstratum clear and colourless; the precipitate was then dissolved in a very little hydrochloric acid, and tested for iron : the conclusion was, that it had been a mixture of reddle and size, for the examination of the supernatant liquor demonstrated the existence of the latter. These were all the facts which came out of the inquiry; and I reasoned upon them in this way:—1st. There could be no doubt that the spots upon the jacket, and waistcoat, and matting, were blood-spots; 2ndly, nor could there be any doubt that this blood had come from the wound in deceased's scalp, for it contained fatty epithelia and hair; 3rdly, the spots upon the sleeve and waistcoat contained coagula of fibrin,the blood, therefore, could not have lost its vitality when it came there, for it is a special and a vital act to produce such a fibre. It is true that this property is often retained by the blood for some hours after the death of the individual, and it might have been a question whether this was not the case in the present instance ; but then there was no such fibrin in the blood upon the matting; that was undoubtedly dead blood, blood that had lost its power of coagulating, and could not have got there, as the prisoner stated, when the blood came upon his jacket; on the contrary, the blood upon his clothes must have been antecedent to that upon the matting. Again, the form and oblique appearance of some of the spots would give a tendency to a fourth conclusion-namely, that it had spurted from a living vessel. Lastly, I came to the conclusion that the stain upon the window beading had been produced by reddle and size, and had been put there to test the accuracy of my other conclusions. With this expression of the facts, I do not know that it is necessary to answer each question put by your correspondent. I may only add, that I have tested the accuracy of my opinions by many previous as well as subsequent examinations, and I am convinced that the presence of fibrin indicates a vitality of the blood; that this vitality is often retained for many hours after the death of the individual, and blood so drawn will often coagulate; but that when the vitality of the blood has ceased, there is never any such clot; the particle of blood when placed with water under the microscope is completely dissolved, and it is as sure an evidence that such blood has either come from a dead body or from blood deprived of its fibrin.-I am, Sir, your obedient servant,
doi:10.1016/s0140-6736(02)89199-1 fatcat:np7sd6srbfefdhacgepsueae6e