PKOCEEDINGS OF SOCIETIES. 53 



protoplasm, occupying the lacunce, and conveyed in minute streams 

 through its structure by the canaliculi, and then described the caucel- 

 late structure of those portions of a bone where considerable strength 

 is required, combined with lightness. Describing the development of 

 bone, he said that it is formed in two ways — from membrane and from 

 cartilage. The bones of the skull are an example of the first method, 

 being first deposited in the centre, and then radiating in all directions. 

 Where bone is developed from cartilage, it commences from several 

 centres, which, by the constant addition of earthy particles, gradually 

 approach each other till they meet. After some additional observa- 

 tions of the nutrition of bone by the periosteum on the exterior and by 

 the medullary membrane on the interior, the lecturer proceeded to 

 consider the chemical constituents of bone ; and in the course of his 

 remarks mentioned that in adult life human bones are composed of 

 one-fourth of animal and three-fourths of earthy matter ; that in 

 infancy these constituents are about equal, whence their liability in 

 children to bend rather than break ; whilst in old age, the earthy 

 matter being greatly in excess (seven to one), bones are much more 

 liable to fracture. Dr. Strong concluded by recommending his hearers 

 to adopt Mr. Squeers's method of investigation, by eating the flesh 

 of their next leg of mutton, and converting the bone into a micro- 

 scopic object. 



The thanks of the meeting having been given to Dr. Strong for his 

 interesting communication, the President remarked that microscopical 

 comparison of the size, form, and proportionate number of bone cells, 

 and the canaliculi radiating from them, had been productive of very 

 imj)ortant results in contributing to our knowledge of some of the 

 remarkable animals which existed on the earth in former ages. As an 

 example of this, he would mention that about the year 1845 Professor 

 Owen read a paper before the Geological Society, on some Ornitliolites 

 (fossil remains of birds) from the chalk, the bone especially described 

 being a portion of the humerus of a (supposed) longi-peunate bird. 

 Subsequent discoveries of similar bones led Dr. Bowerbank to believe 

 that these so-called bird bones were those of the great flying reptile, 

 the Pterodactyl. By one of those strange coincidences of thought 

 which not unfrequently happen in scientific investigation. Professor 

 Quekett was also impressed with their similarity, and he and Dr. 

 Bowerbank — neither of them aware of the experiments which the 

 other was pursuing — determined upon a close microscopical examina- 

 tion of the structural peculiarities of the bones, in the hope of eliciting 

 some characters which would, in conjimction with their external forms, 

 point out with some degree of certainty the class of animals to which 

 these remains in reality belonged. They arrived independently at 

 the same conclusion — that the bones of birds, reptiles, fishes, and 

 mammals, each possess marked peculiarities which furnish a means of 

 deciding disputed relations of obscure and difficult tribes of existing 

 animals, as well as of ascertaining the triie relations of such palseon- 

 tological remains as it might be otherwise difficult or impossible, from 

 their dilapidated condition, to refer to their real position amongst 

 animals. In illustration of Dr. Strong's paper, Mr. Lee also exhibited 



