PROPERTIES OF THE BLOOD. 31 



EXPERIMENT XI. 



In the month of June, when the thermometer in the shade 

 stood at 67, I bled a man who had laboured under a phthisis 

 pulmonalis for some months, and at that time complained of a 

 pain in his side. The blood, though it came out in a small 

 stream, yet flowed with such velocity, that it soon filled the 

 basin. After tying up his arm I attended to the blood, and 

 observed that the surface became transparent, and that the 

 transparency gradually went deeper and deeper, the blood being 



are favorable to this view ; but Miilder g asserts that there is a difference 

 between albumen and fibrin of one equivalent of sulphur in every ten 

 equivalents of protein. Denis h supposes liquid albumen to be a salino- 

 alkaline solution of fibrin, a portion of which, precipitated during co- 

 agulation, he thinks is the fibrin of the blood. But it is well known 1 

 that serum is not rendered turbid by many acids. Denis says that 

 1000 parts of water, charged with 100th part of nitre, and 1000th of 

 soda, dissolves about /OOths of fibrin, producing a fluid with all the 

 properties of serum. M. WurtzJ gives an account of a mode of pre- 

 paring albumen which is soluble without the aid of an alkali or salt. 



Dr. Buchanan, k like the older observers, regards fibrin as a mere 

 modification of serum ; and the results of his experiments, in which a 

 mixture of serum from blood and serum from a serous cavity was found 

 to coagulate spontaneously, appear to me fully to warrant his conclu- 

 sion, which is not inconsistent with Liebig's, and to afford a simple ex- 

 planation of the formation of some of the most important healthy and 

 morbid products. In mixtures of serum of blood with serum either 

 from the pericardium, pleura, or vaginal tunic of the testicle, I have 

 seen the coagulum Assume various forms, not distinguishable from more 

 permanent structures. Sometimes it would be apparently a homogeneous 

 transparent jelly, either contracting but slightly or not at all, or so 

 greatly as to. form less than a third of the bulk of the serum ; often 

 presenting the character of a closed membrane of the utmost delicacy, 

 with processes running towards the centre, and forming cells for the 

 contained fluid : and occasionally a portion of the clot would be white and 

 nearly opake, somewhat resembling the cicatricula of a fowl's egg. The 

 ultimate structure of the membranous part was composed of most delicate 

 fibrils, as stated in Note vui ; and faint round molecules of extreme 

 minuteness were interspersed here and there. I may add that in several 

 trials the fluids were filtered both before and after mixing ; and that it 

 was clearly ascertained that neither of them would coagulate spontane- 



s Chemistry of Vegetable and Animal * J. Davy's Researches, ii, 93 et seq. 



Physiology, 8vo, part ii, p. 314. J Mr. Paget's Report, Br. and For. Med. 



h Essai sur I'Application de la Chimie a Rev. vol. 21, p. 541. 



1'Etude physiol. du Sang de THomme, k London Medical Gazette, xviii, pp. 



p. 81, 8vo," Paris, 1838. 50 et seq. 



