342 ANNUAL OF SCIENTIFIC DISCOVERY. 



organic and inorganic structures was that while an inorganic structure must 

 be in a state of unstable equilibrium, an organic structure must be in a state 

 of stable equilibrium. This, he thought, was the fundamental idea of the 

 structure of almost all organic bodies, and to accomplish this the solid parts 

 were connected together by something more or less approximating to a per- 

 fect fluid. He would consider in the case of fluids what would be the grand 

 classification. He had demonstrated that there were but four forms in which 

 one fluid lying in another of equal specific gravity, as in the case of the em- 

 bryo, would remain in equilibrium and not crowd together in a sphere. The 

 geometer as well as the naturalist was therefore obliged to divide the subject 

 into four parts. One of them would be the form of a ring radiating about its 

 own axes, which he took to be the fundamental idea of the radiata. The 

 molluscs would be represented by an eliptical cylinder, the form of their 

 embryo.; the articulata by a cylinder w r ith constrictions at regular distances, a 

 shape produced by the revolution of a wavy line round the axis of the cylin- 

 der, and the vertebrata by a double cylinder having a regular side and corre- 

 sponding to the spinal marrow and the intestinal cavity. The length of the 

 limb would be determined by the vibration of the pendulum. On the ways 

 and means of locomotion there were a great many different points on which 

 light might be thrown by the geometer, not that the geometer had any right 

 to suppose that he was getting at the fundamental idea of the subject, but he 

 was assisting the naturalist. 



Professor Agassiz in commenting on this communication said that the work 

 of the system was not ours, but our Creator's. We could not but come to 

 the conclusion, from a consideration of the whole, that it was all devised in 

 order to place man at the head, and millions of ages ago his coming was seen 

 as the culmination of the thought which devised the fishes and the lowest ra- 

 diata. When we came to the deep conviction that this whole was the com- 

 bination of these facts in a logical manner, and as whatever intelligence we 

 had was derived from Him and in His image, that coincidence made it possi- 

 ble for us to understand His objects. 



ON THE DISTINCTIONS SUPPOSED TO LIMIT THE VEGETABLE 



AND ANIMAL KINGDOMS. 



The following is an abstract of a lecture on the above subject delivered be- 

 fore the Royal Institution by Professor Lankester, F.R.S. : 



In commencing, the lecturer made some general remarks on classification, 

 and pointed out the importance of accurate definitions in order to constitute 

 the classes, families, genera, and species of the naturalist. The importance 

 of defining species was greater than that of larger groups, because these were 

 composed of species. As genera were collections of species, and families 

 collections of genera, so the animal and vegetable kingdoms were but col- 

 lections of species. The difficulty in distinguishing between the animal and 

 vegetable kingdoms consisted in our imperfect knowledge of the character of 

 species which existed on what might be called the limits of the two king- 

 doms. The history of the attempts at defining animals and plants, for sys- 



