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served at the seat of the foreign body. The fact of the non-removal of dentine 

 and enamel was one which seemed to him to tell strongly against the notion of 

 Pangenesis. The tooth structures, he believed, were not at all renewed. The 

 statement, therefore, which was so often met with, "that all the tissues of 

 the body are being constantly removed and renewed," could only be received as 

 true in a very general sense. Really the several tissues differ remarkably in 

 this respect — some being replenished even in the course of a few hours, whilst 

 others remain for seventy or eighty years without undergoing any nutritive 

 changes whatever. It was, however, to be observed, that the enamel of the 

 tooth was not nearly so brittle whilst in connection with the living body as it 

 became after having been removed for many years, and from this circumstance 

 he should conclude that during life even this hard tissue was permeable to a 

 slight extent. So, also, if a tooth was weighed soon after removal, it would be 

 found that its weight was greater then than after being subjected to desiccation 

 in a hot air chamber, proving that the hard tooth structure really contained a 

 little water, He did not think that the tooth was one of those tissues nearly 

 allied to bone, for bone was replenished faster than muscle or nerve and, 

 therefore, it differs from tooth materially in this respect. This was 

 one of the reasons which induced him to think that the tooth was 

 allied to horn or Epithelium rather than to bone, although the point was 

 one freely open to discussion. Another very important subject had been touched 

 upon, and that was the distribution of nerves in the tooth pulp. The specimen 

 which Mr. White exhibited, and to which he had already called the attention of 

 the members, showed the distribution of the nerves in a remarkably perfect 

 manner, and many persons would be surprised to learn that there is no drawing 

 extant which shows their distribution so admirably as it appears in this speci- 

 men. German worshippers would, no doubt, blame him for remarking that no 

 one there has yet given an accurate drawing of nerve fibres near their distribution 

 in such tissues as the tooth pulp. Yet such was undoubtedly the case, and in 

 one of the last memoirs on the distribution of nerves — which appeared in the last 

 number of Max Schultz's " Archives"— they might see the nerves drawn as if 

 they were straight, parallel rods, running side by side ; but it was quite certain 

 that no one who had actually seen their arrangement in nature would have repre- 

 sented them as in these drawings. Every student knows that although a nerve 

 looks like a piece of fibrous cord composed of parallel fibres, he cannot tear it 

 longitudinally, and the reason is that nerve fibres are arranged in a plexiform 

 manner, that they are continually crossing from one to the other side of the nerve 

 trunk, and that they are never found running in straight parallel lines, even for 

 the distance of the ,~ of an inch. Even where there are only two minute fibres 

 less than the id l m of an inch in diameter together, they pass spirally round one 

 another, and yet this simple fact is not represented in any foreign work with 

 which he was acquainted. They could not possibly exist as they were shewn in 

 these German drawings, and they would inevitably become deranged if they 

 were placed as drawn. If the members would look at Mr. White's specimen, 

 they would see very clearly this beautiful undulating plexiform arrangement. 

 He thought it was most probable that they did end in loops, although, for the 

 reasons named by Mr. White, this had not yet been clearly traced, but it was 

 certain that nerves formed in every part of their course a wonderful plexus. 

 Terminal plexuses would be found in the sheaths of all the hairs and the num- 

 ber of ultimate nerve fibres in such tissues was enormous. It was most sur- 

 prising to find that whilst many German observers had traced them to end in 



