232 Professor Victor Horsley [April 6, 



order of the velocities of the bullets, shows immediately the unreality 

 of the notion. In every case the particles of the substance are hurried 

 forward (particularly evident in the casts before mentioned) in front 

 of the bullet, and thus by increasing the size of the moving mass such 

 particles practically constitute a larger projectile. Much destruction 

 is due to this, as Delorme has more particularly demonstrated in the 

 well-known case of firing a bullet into a book, wherein one may see 

 the laceration of the pages successively increased, although the 

 momentum of the bullet is steadily diminishing, and in proportion to 

 the increasing laceration so discs of increasing diameter are found in 

 the cavity, having been cut from the preceding pages. The hurrying 

 forward of the particles is very beautifully shown by Professor Boys 

 in his photographs of the debris of glass plates after a bullet has 

 passed through them. In one case a large fragment of glass is shown 

 to be moving parallel to the bullet, i.e. with the same velocity. This 

 question of accessory damage is of much importance to the patho- 

 logical 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 

 Professor Boys' photographic record. 



(b) 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 common result of the 

 employment of leaden bullets, and a result which is wholly dependent 

 on the principle just enunciated. In the photograph of the penetra- 

 tion 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, how- 

 ever, 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 

 plate, 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. 



(c) 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 

 firearms, and endless have been the suggestions put forward to 

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



