234. Professor Victor Horsley [April 6 



tained water in large quantity and that the energy of the moving 

 projectile being imparted to the particles of water, caused the disper- 

 sion of these in a hydrodynamic fashion. Kocher, in 1874 to 1876, 

 was the first who thoroughly dealt with this question in the manner 

 shadowed forth by Huguier, and he proved, in a series of interesting 

 experiments, which Dr. Kramer and myself have fully confirmed, that 

 the effect is really a hydrodynamic one. One of the simplest of his 

 observations you see before you, and is made as follows : — Two tin 

 canisters are taken of precisely the same size and strength, and are 

 filled with equal quantities of lint ; but in the one case the lint is 

 dry, in the other saturated with water. "When a bullet of moderate 

 velocity is fired through these canisters, it simply perforates the dry 

 one, but causes the wet one to burst explosively. It is, however, not 

 a simple question in dealing with these artificial schemata merely to 

 provide a porous substance the cavities of which are filled with water, 

 for I have found that if the intervening septa are strong, as, for 

 instance, in the case of sponge, that the bursting effect is not so great. 

 In fact, the water must be thoroughly incorporated with the substance, 

 or, to speak more correctly, the substance must be more perfectly fluid. 

 This can be easily demonstrated by taking dough containing different 

 percentages of water, and since dough is a substance in which the in- 

 corporation of the water is very complete, it affords a particularly 

 good example to employ. By firing bullets of precisely the same 

 velocity through these samples, you see that the destruction is effected 

 strictly proportionally to the fluidity of each specimen. This is the 

 reason why it is really of no absolute value to make experiments on 

 dead tissues, for the brain in a state of rigor mortis is practically a 

 solid, since both its living protoplasm and blood in the blood-vessels 

 have coagulated, whereas in the living condition the firtt is semi-fluid 

 and the second quite fluid. It was to investigate this point, as well 

 as the previous questions, that I have paid more especial attention to 

 the proportionate relation existing between the velocity and the 

 explosive effect. The results are very obvious in the casts before 

 you. This work has been immensely facilitated by the kindness of 

 Sir Andrew Noble, who caused to be constructed at my request a 

 modification of a 22-calibre rifle, whereby I can fire a 40-grain bullet 

 with any velocity I wish from a few hundred feet per second to over 

 3500 feet per second. 



The casts show that the effect in the clay is proportional to (1) 

 the velocity of the bullet, (2) the wetness of the clay. 



The method of proof is so convincing I need not detain you further 

 in this discussion. 



Since the question is, we now see, all-important, it becomes a 

 matter of no small- moment to study the effect exerted by bullets 

 entering fluid (for example, water). In the first place, as may be 

 seen by these experiments, the effect of the perforation of a skull, 

 filled with water, by a bullet, as was first done by Kocher, is to cause 

 the bursting of the sutures. I would draw your attention to the fact 



