io6 



NATURE 



[May 31, 1894 



same velocity. This question of accessory damage is of 

 much importance to the pathological problem how much 

 damage is effected in the brain. I have found discs of 

 bone forced through the brain, such discs (as will appear 

 directly^ being Larger than the projectile itself. Small 

 fragments are also hurried forward with the same velocity 

 as the bullet, as these casts show, the plaster method 

 thus confirming Prof. Boys' photographic record. 



(^) Sectional Area. — From what has just been said, it 

 is plain that the crushing effect of the bullet will be 

 greatly increased if its diameter is enlarged ; and it is 

 understood that this was the reason why the Duke of 

 Wellington opposed the introduction of the smaller bore 

 weapon for the old musket called " Brown Bess.' But few 

 words, therefore, are requisite in dealing with this point. 

 I wish, however, to draw attention to an extremely com- 

 mon result of the employment of leaden bullets, and a 

 result which is wholly dependent on the principle just 

 enunciated. In a photograph of the penetration of an 

 iron plate by the magazine rifle bullet, it will be noticed 

 that the diameter of the holes is almost twice that of 

 the bullet as it leaves the muzzle of the rifle. When 

 the bullet is picked up, however, after it has passed 

 through the plate, the reason of this seeming absurdity 

 is at once recognised, for the bullet is compressed into 

 a hard mass of lead and nickel by its first impact on the 

 front of the plale. of the size of the hole shown. It is 

 important, therefore, for the military surgeon to consider 

 what proportion of the damage is due to deformation of 

 the projectile on its striking the body, but the sectional 

 area demands very little attention when compared to the 

 velocity as a source of destruction. 



(f) Heating. — The notion that a bullet produced some 

 of its destructive effects in consequence of its being 

 raised in temperature, as a natural result of some of its 

 momentum being converted into heat, has always been 

 before scientists ever since the invention of fire-arms, and 

 endless have been the suggestions put forward to support 

 this idea. I am not going to waste your time on the 

 matter because, in spite of the plausible papers of Hagen- 

 bach and Socin, there are certain facts plain and simple 

 enough which, to my mind, completely dispose of the 

 notion put forward by those authors, namely that the 

 bullet undergoing deformation on striking a hard sub- 

 stance like bone becomes heated so intensely that it 

 partly fuses. The simplest observation of all is that, I 

 think, made by von Beck, and which 1 have often con- 

 firmed, namely that a bullet, though completely deformed 

 by impact, may enclose a hair or piece of wood without 

 these being in the least degree altered by heat ; while as 

 for its being heated in the barrel, Sic, that cannot amount 

 to 40 C, for Messner has shown that a bullet traversing 

 dirty clothing carries with it living microbes, and deposits 

 them in the object it strikes, still in a living state, so that 

 they grow therein if the soil is a suitable one ; and these 

 observations have been fully confirmed by Delorine and 

 Laveran. It is to be hoped that we have heard the last 

 of this unquestionably exaggerated idea of the heating 

 of a bullet 



(2) Factors due to the physical constitution of the 

 solid. 



We now enter upon the discussion of the most inter- 

 esting of all the physical considerations determining the 

 well-known bursting effect which a bullet produces on 

 certain substances, e.g. clay, brain, &c., while simply 

 perforating others, e.g. wood, iron, &c. The reason why 

 a bullet behaves apparently quite differently when it is 

 forcing its way through solids of different kinds, has 

 been, as a matter of fact, answered ever since 1S4S, when 

 Huguier made some remarkable, but little known, re- 

 searches of the effects of bullets on soft tissues, after he 

 had observed the results of the wounds inflicted in the 

 fighting in I'aris in 184}). It will be remembered that in 

 that struggle, as in others, the appearance of bursting 



NO. 1283, VOL. 50] 



within the tissues was very noteworthy, and gave rise to 

 the notion of explosive bullets having been employed by 

 the combatants contrary to the received opinions of 

 international comity. The whole question is a perfectly 

 simple matter, and resolves itself merely into the proposi- 

 tion that destructive effects vary in direct proportion to 

 the cohesiveness, ;.<-. the fluidity of the particles com- 

 posing the body. Ever since the observations of Tresca, 

 Roberts-.Vusten.and others, we have been made familiar 

 with the phenomenon of the flow of metals when these are 

 subjected to powerful pressure, and the mode of the dis- 

 placement of the particles has always been compared to 

 the displacement observed in viscous fluids. The extreme 

 case in which fluidity is least present is that of the sub- 

 stances which we term brittle. In these, while much 

 pulverisation occurs, the displacement of particles later- 

 ally is very slightly marked. Contrast the penetration of 

 an example of this class, namely a flat, thin bone, with 

 the effect produced on a more or less plastic solid 

 like brain, and a striking ditt'erence presents itself, for 

 whereas the bone is simply penetrated in the long axis 

 of the bullet, the brain is thrown aside in every direction. 

 Huguier made observations on certain dead organs, 

 e.g. lung, liver, &c.,and suggested that the reason why 

 there was so much lateral disturbance was that the tissues 

 contained water in large quantity, and that the energy of 

 the moving projectile being imparted to the particles of 

 water, caused the dispersion of these in a hydrodynamic 

 fashion. Kocher, in 1S74 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 etfect is really a hydro- 

 dynamic 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 t .e dry one, 

 but causes the wet one to burst explosively. It is, how- 

 ever, 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 elYect is not so 

 great. In fact, the water must be thoroughly incor- 

 porated 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 incorporation 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 pr.aclically a solid, since both its living 

 protoplasm and blood in the blood-vessels has coagulated, 

 whereas in the living condition the first is semi-fluid, and 

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

 as well as the previous questions, that 1 have paid more 

 especial attention to the proportionate relation existing 

 between the velocity and the explosive effect. The re- 

 sult'^ are very obvious in the casts before you. This work 

 has been immensely facilitated by the kindness of Sii 

 Andrew Noble, who caused to be constructed at my re- 

 quest 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 propor- 

 tional to (I) the velocity of the bullet, (a) the wetness of 

 the clay. 



