164 THE BLOOD. 



birds is remarkable for the rapidity of its coagulation, and is 

 therefore not so well adapted to experiments relative to the 

 circumstances which attend this process as the blood of 

 animals in which coagulation is less rapid. The experiments 

 referred to are imperfect, and no attempt is made to invali- 

 date the accuracy of the observations of Richardson on the 

 blood of mammals and the human subject. 



The most recent experiments on this subject are by Jo- 

 seph Lister, published in a lecture on " Coagulation of the 

 Blood," in the " London Lancet," February, 1864. The view 

 entertained by Mr. Lister is, that the blood is kept fluid in 

 the organism by its contact with living parts ; and that all 

 other contact, especially that of inorganic bodies, produces a 

 tendency in this fluid to coagulate. The power of retaining 

 the fluidity of the blood he supposes to reside particularly in 

 the coats of the blood-vessels, but he further says : " I think it 

 probable, though not yet proved, that all living tissues have 

 these properties with reference to the blood." ' The ammonia 

 theory he considers entirely fallacious, and ascribes coagula- 

 tion either to the contact of animal tissues after death, when 

 their vital property of maintaining the fluidity of the blood 

 slowly disappears, or the contact of ordinary matter. 2 



Various experiments are cited in support of the view thus 

 briefly given. In one of them, the author, by an ingenious 

 mechanism, draws the blood into an apparatus consisting of 

 a tube in which it is effectually secluded from the air, and 

 which allows the fluid to be stirred with a little wire which 

 is provided with projecting spokes. In one experiment the 

 tube was filled with blood, which did not come in contact 

 with the air, and the blood stirred with the wire. In thirty- 

 seven minutes the wire was removed and found enveloped in 

 a mass of clot. In another experiment, "Receiving blood 

 from the throat of a bullock into two similar wide-mouthed 



1 London Lancet, American rcpublication, Feb. 1864, p. 91. 



2 This view, as stated by Mr. Lister, was entertained by Astley Cooper, Thack- 

 rah, Brucke, and others. 



