12 Proceedings of the Boyal Physical Society. 



notable instance of this prejudiced explanation lias been often 

 quoted in the theories advanced, to explain the existence of 

 organic remains in the crust of the earth. Marine organ- 

 isms, fishes, shells, corals, were found embedded in the rocks, 

 far removed from the existing sea, and at considerable heights 

 above its level. It was contrary to their theories to believe 

 that the sea had ever occupied the position in which the 

 marine fossils were found. If not, how came they to get 

 there. The reply was a resolute denial, that the fossils were 

 the relics of marine animals, and the phenomena were really 

 explained by supposing a " plastic power " in nature, wdiich 

 exerted itself in moulding the living rock into mimic repre- 

 sentations of plants and animals. 



In the sixteenth century, with the revival of learning, a 

 better era dawned upon the study of E'atural History. This 

 originated with Belon of Mans, who was born in 1517, and 

 seems to have devoted himself to the study of birds, fishes, 

 and botany, In the year 1554, two works on fishes appeared 

 — one by Eondelet, Professor of Medicine at Montpellier, the 

 other by Salviani, a physician at Eonie. These were soon 

 followed by two writers on General Zoology — Conrad Gesner, 

 and Ulysses Aldrovandi, the former a physician at Zurich, the 

 latter a Professor of Philosophy and Natural History in the 

 University of Bologna. Gesner, in his history of animals, 

 classifies them into tw^o great divisions — those that reside on 

 land, and those that live in the water. The viviparous quad- 

 rupeds are subdivided into six orders, into which families are 

 disposed according to the accident of their being wild or tame. 

 Aldrovandi adopts Plato's division of the animal kingdom, cor- 

 responding to the four elements of the ancients — viz., fire, air, 

 earth, and water. He begins with birds, " that division," as 

 he says, " seeming to offer itself first in order ; for as to those 

 corresponding to fire," he observes, "I consider none such 

 exist." There are many important anatomical and physio- 

 logical details in the works of those authors. For example, 

 Aldrovandi describes the process of incubation in the Qgg for 

 each day, the ''punctum saliens" having been seen on the 

 third, with the " truncus venosus " arising from it. 



The small band of active naturalists who flourished during 



