i82 LEISURE-TIME STUDIES. 



birth to higher forms of life, is refuted in a similar manner by 

 microscopic evidence. Appearances are proverbially decep- 

 tive, and the naturalist requires evidence reaching beyond that 

 furnished by mere appearances to justify a belief in trans- 

 formations of so marvellous a nature as those described. The 

 present attitude of science towards this subject is marked by 

 a strong desire for the termination of the controversy, and 

 for the institution of some crucial tests and experiments the 

 results of which can be submitted for judgment to the world 

 at large. There can, however, be little doubt of the over- 

 weighting influence which the theory of biogenesis possesses 

 over spontaneous generation in the minds of the vast majority 

 of thinking persons. For the support of the former doctrines, 

 we are called upon to infringe no one law of nature. Spon- 

 taneous generation, as we have seen, begins by assuming the 

 operation of a law which, as far as exact science at present 

 shows, is unrepresented in the whole of nature's domain. 

 The perfect harmony of biogenesis, and its clear analogies 

 with the laws of natural development at large, constitute, as 

 we have seen, strong points in its favour; and the matter 

 may be fitly summed up in the words of one of the most able 

 and critical of modern biologists, when he declares that 

 " the present state of our knowledge furnishes us with no 

 link between the living and the not -living." 



The present subject links itself in an intimate manner 

 with some of the highest interests of mankind. Aided by 

 the methods of research practised in experiments on bio- 

 genesis, naturalists have successfully eradicated some grave 

 diseases of the lower animals. Furnished with saving 

 knowledge of a like kind, physicians are combating the 

 diseases of humanity with new weapons, and with at least 

 fair promise of effecting in due time the repression of the 

 epidemic disorders which periodically decimate the popula- 

 tions of the globe. And our reflections on the means of 

 physical salvation which science thus places at our disposal, 

 should certainly be tempered with grateful memories of the 

 older biologists who took the first steps in a line of research 

 fraught with good to all succeeding generations. 



