THE ORIGIN OF VERTEBRATES. 



By Wir.tiAM Hammond Tooke. 



The fascination which such subjects as the origin of species 

 and races, and their subsequent development, have exerted on 

 the mind of the writer, must be his excuse for venturing into 

 somewhat unaccustomed fields, and for the endeavour to place 

 before those in South Africa, who take an interest in these 

 matters, a remarkable theory which for some years has been 

 propounded and defended by a biologist of repute*, but which, 

 perhaps, has even yet not become as widely known as it deserves, 

 whether as a genuine contribution to scientific knowledge, or as 

 a masterly display of instructed dialectic. If the imperfect 

 sketch attempted in this paper should attract the attention of 

 those better qualified than himself to appraise and appreciate 

 Dr. Gaskell's theory, the object of the present writer will have 

 been attained. 



The volume in which Dr. Gaskell's views are set forth and 

 expounded is introduced by a ciuotation from a private letter., 

 addressed by the late Professor Huxley to the author in 1889, 

 as follows : — 



"Go on and prosper; there is nothing so useful in Science as one 

 of those earthquake hypotheses which oblige one to face the possibility 

 that the solidest-looking structures may collapse." 



The hypothesis, the enunciation of which constitutes the 

 substance of this work, is certainly daring, if not earth-shaking. 

 But, in order to consider it we must place before us the doctrine 

 of evolution, or descent with relation to organic life, which the 

 recent centenary of Darwin mu.st have made familiar to all. 

 According to the text-books it is this : That animals and plants 

 now existing (for we shall not venture into the inorganic world) 

 arose by a natural evolution from simpler pre-existing forms of 

 life ; those from still simpler, and so on back to a simplicity of 

 life such as that now represented by the very lowest organism. t 



Dr. Gaskell's position, in a few words, is as follows : The 

 evolution of animal life is a process of upward progress, cul- 

 minating in the highest form — man ; and toward this upward 

 progress the most essential organ, or group of organs, is the 

 nervous system, or brain. Or, as he siuns it up at the end of 

 the volume : — 



" 'Die law for the whole animal kingdom is the same as that for 

 the individual; success in this world depends upon brain.' 



In the original coelenterate stock J this central nervous sys- 

 tem naturally centred and clustered round that most important 



* " The Origin of Vertebrates," by Walter Holbrook Gaskell, pp. x,. 

 538. London: 1908 (Longmans. Green and Co.). 

 t Thomson, " Outlines of ZoologA%" chap. vi. 

 t Coelenterata or Radiata = sea-anemones, jelly-fish, etc. 



