hunter's posthumous paper on fossils. 327 



" Some shells are turned into chalk. It would appear in all of the 

 encrine kind, as also the Echinus, that after a mould had formed all 

 around, and also in the Echinus, the shell filled up ; that the shell had 

 dissolved and crystallized again, and in a particular manner, for they 

 break in flakes. This appears to he universally [the case] with all 

 those substances." — P. lv. 



Geological research, since Hunter's time, has confirmed his conclu- 

 sion that the flat-tract, or valley, of the Thames, was once an area of 

 the sea, or a vast estuary, receiving, however, in addition to remains of 

 its own sea-inhabitants, occasional contributions, by a more ancient 

 river, from some adjoining continent, in the form of great serpents, sea- 

 turtles, singular quadrupeds, bike the Coryphodon, Pliolophus, and 

 Hyracoiherium, of genera now unknown; and plants of a tropical 

 character, such as the fruits of the Palms of the genus Nipa, which is 

 allied to the Pandanus and cocoa-nut palm ; of species of Anona or 

 custard- apple ; and of Acacice, which, although less decidedly tropical, 

 imply a warm climate. 



Permit me to refer to one other example of Hunter's special geolo- 

 gical observations, made at a comparatively early period of his life, 

 when he was serving, as surgeon, with the English army in Portugal. 

 "We have long known that the employment of his leisure and oppor- 

 tunities, in that capacity, was most exemplary to all young surgeons 

 similarly circumstanced : the temptations to enjoy, in a fine and 

 voluptuous climate, the hours not required in the routine of strict 

 military duty are such as few resist : the conditions for devoting those 

 leisure hours to special scientific pursuits, are generally anything but 

 favourable or encouraging. But they in no degree abated Hunter's 

 ardour in the pursuit of truth : nothing was suffered to impede his 

 observations, dissections, experiments, and collections of natural history. 

 His museum still shows the preparations he made of Portuguese lizards 

 and other indigenous species, which he succeeded in bringing home, in 

 1763, and which formed, indeed, the nucleus of his great collection of 

 comparative anatomy. 



That Hunter, whilst with the army in Portugal, laid the foundation 

 of his principles of physiology, and of the physiological treatment of 

 disease and injury, finally set forth in his work ' On the Blood, Inflam- 

 mation, and Gun-shot Wounds,' is part of the history of surgery. 



Most of my physiological hearers may recollect that it was in a 

 gentleman's garden in Portugal that Hunter made the experiment 

 determining the possession of the sense of hearing in fishes, of which 

 sense he believed that he had first discovered the organ in that class. 

 But science has not hitherto known, or had any ground for surmising, 



