i8 94 .] 



THE BRITISH NATURALIST. 



7i 



possessed by some worms, but the lungs of land molluscs, like those of 

 scorpions, are a special development not homologous to similar organs 

 in any other group. 



The gill of the highest existing fish is the " lineal descendant " and 

 " direct representative," if I may be allowed the phrase (it is simpler 

 than homologous), of that ol some worm-like form akin to the existing 

 Balanoglossus ; whilst the lungs of man form the last term of a series 

 beginning in the swimming bladder of some ancient Silurian fish. I 

 say the last term advisedly, for though some people talk glibly of 

 an animal higher than man who in the far-off future will succeed 

 us on this planet, it seems to me that such speculations are not 

 only not supported by reason but opposed to it. When our planet 

 had, in the inconceivably remote past, sufficiently cooled for its vaporous 

 envelope to condense into an ocean whose temperature was low enough 

 for the existence of living organisms, then living organisms appeared. 

 How they came into existence we do not know, but may be allowed to 

 protest against the unscientific assumption of some so-called scientific men 

 who profess to deem it beyond reasonable doubt that the primordial 

 protoplasm arose from the fortuitous concourse of the atoms of its 

 constituents. So far as we know, the living always arise from the living, 

 we have absolutely no experience of the living arising from the not-living : 

 Many wonders have been worked in the laboratories of synthetical 

 chemists, but this wonder of wonders has not yet rewarded the labour of 

 patient students, and the soberest and profoundest of them can see no 

 prospect of its achievement. To those who, on other grounds, believe in 

 God and regard the universe as an expression of the Supreme mind, in 

 itself in the strictest sense unknowable by us, it will not seem necessary 

 to enlarge upon the absurdity of treating as a scientific truth the un- 

 scientific hypothesis which has found favour in the sight of soma ultra- 

 materialists, and whether we apply the term " creation " or ''formation " 

 to the appearance of the first living being on earth, either term simply 

 serves to indicate our utter ignorance of how the first protist came into 

 existence. 



So far as we can judge from the geological record, the earliest 

 specialization of the primitive protists was in the direction of foraminifera 

 and diatoms, and the first organic rocks were formed by the heaping up 

 on the ocean floor of their calcareous shells and siliceous cases. It is 

 probable that for thousands of centuries no higher organisms than protists 

 existed on earth, and that for periods long subsequent nothing higher 

 than what we now regard as lowly plants and animals succeeded. 



After many upheavals and depressions, accompanied as is probable by 

 occasional earth convulsions of a violent character, by a gradual though 

 slight diminution of temperature and by a much greater degree of 

 specialization in the fauna than had occurred in earlier periods of equal 



