40 THE ANATOMY OF INVERTEBRATED ANIMALS. 



It is argued that a belief in abiogenesis is a necessary- 

 corollary from the doctrine of Evolution. This may be true 

 of the occurrence of abiogenesis at some time; but if the 

 present day, or any recorded epoch of geological time, be in 

 question, the exact contrary holds good. If all living beings 

 have been evolved from preexisting forms of life, it is enough 

 that a single particle of living protoplasm should once have 

 appeared on the globe, as the result of no matter what agency. 

 In the eyes of a consistent evolutionist, any further indepen- 

 dent formation of protoplasm would be sheer waste. 



The production of living matter since the time of its first 

 appearance, only by way of biogenesis, implies that the spe- 

 cific forms of the lower kinds of life have undergone but little 

 change in the course of geological time, and this is said to be 

 inconsistent with the doctrine of evolution. But, in the first 

 place, the fact is not inconsistent with the doctrine of evolu- 

 tion properly understood, that doctrine being perfectly con- 

 sistent with either the progression, the retrogression, or the 

 stationary condition, of any particular species for indefinite 

 periods of time ; and, secondly, if it were, it would be so much 

 the worse for the doctrine of evolution, inasmuch as it is un- 

 questionably true that certain, even highly-organized, forms 

 of life have persisted without any sensible change for very 

 long periods. The Terebratula psittacea of the present day, 

 for example, is not distinguishable from that of the Cretaceous 

 epoch, while the highly-organized Teleostean fish, Beryx, of 

 the Chalk, differed only in minute specific characters from 

 that which now lives. Is it seriously suggested that the ex- 

 isting lerebratulm and JBeryces are not the lineal descendants 

 of their Cretaceous ancestors, but that their modern repre- 

 sentatives have been independently developed from primordial 

 germs in the interval ? But if this is too fantastic a sugges- 

 tion for grave consideration, why are we to believe that the 

 Globigerinw of the present day are not lineally descended 

 from the Cretaceous forms ? And, if their unchanged genera- 

 tions have succeeded one another for all the enormous time 

 represented by the deposition of the Chalk and that of the 

 Tertiary and Quaternary deposits, what difficulty is there in 

 supposing that they may not have persisted unchanged for a 

 greatly longer period ? 



The fact is, that at the present moment there is not a 

 shadow of trustworthy direct evidence that abiogenesis does 

 take place, or has taken place, within the period during 

 which the existence of life on the globe is recorded. But it 



