AN ADDRESS ON THE TREATMENT OE WOUNDS 281 



to press out the serum. In the other part of the experiment the water was 

 introduced before the blood into the purified bottles which were to receive it, 

 so that any organisms which the water contained were diffused in the entire 

 mass of the blood before coagulation, and were presumably retained in the clot 

 when it shrank and pressed out the serum. And unexpectedly great as the 

 resisting power of the serum to the development of micro-organisms proved to 

 be, that of the coagulum seemed markedly greater. But our knowledge of the 

 remarkable influence of the quantity of the ferment in proportion to the serum, 

 as indicated by the more recent experiments, makes the evidence on which 

 I relied at the Cambridge meeting far from conclusive,^ so that I cannot now 

 regard it as demonstrated for blood outside the body that the coagulum has 

 a greater power than the serum of resisting putrefaction. But what I desire 

 particularly to mention on the present occasion is an experiment with reference 

 to the behaviour of the coagulum under the circumstances in which it especiallv 

 interests us as surgeons — viz. within the living body. The experiment was of 

 a character such as it w^ould have been difficult under existing circumstances 

 to perform in London, so I resorted to the Ecole Veterinaire of Toulouse, where 

 everything was most liberally placed at my disposal by my friend Professor 

 Toussaint and others in authoritv at the institution. 



Having provided four pieces of glass tube, each about an inch and a half 

 in length and three-hundredths of an inch in diameter, containing two pieces 



of silver wire (W) twisted together, with a little piece of ^ 



fine linen cloth (L) fixed between them at their central i*) V^^ 



part, the whole apparatus having been purified by 



steeping in a strong watery solution of carbolic acid, and subsequent boiling 



in water and drying over a lamp, I applied to each bit of linen one-twentieth of 



a minim of septic liquid, which was in the case of one of the tubes undiluted 



putrid blood, in the second that blood diluted with ten parts of pure (boiled) 



^ If septic liquid is diffused through blood before its coagulation, the bacteria are probably almost 

 all, if not all, entangled in the meshes of the fibrine, and retained by them when the scrum is pressed 

 out by the shrinking clot. On the other hand, if the liquid of inoculation is added after the contraction 

 of the coagulum, the bacteria are, in the first instance, confined to the scrum. Hence, supposing the 

 serum and clot alike in their resistance to bacteric development, we should expect, according to our 

 present knowledge, that different results would follow such a comparative experiment, according as 

 the serum was large or small in amount in proportion to the clot. Thus, when the scrum is relatively 

 scanty, as is the case with the blood of the ox, which was the subject of the experiment related at Cam- 

 bridge, if a very dilute septic liquid were blended with the blood before coagulation, the bacteria, few 

 in proportion to the bulky clot, might fail to develop in it ; but if a corresponding quantity of the same 

 Uquid were dropped in after the clot had contracted, the bacteria, concentrated in the smaller quantity 

 of serum, might succeed in growing in it. Observations of such a character cannot, therefore, be regarded 

 as affording evidence of any special resisting power on the part of the coagulum as compared with the 

 serum, unless an estimate is made of the relative amounts of serum and clot in the particular blood 

 which is the subject of experiment, and a judgement formed accordingly. 



LISTER II U 



