650 POPULAR SCIENCE MONTHLY, 



neither appears except in the presence of the other. The inherit- 

 ance of acquired characters is also made a corollary of monistic 

 belief. 



Now, all these hypotheses are possibly true, but none of them 

 are as yet conclusions of science. They meet the conditions re- 

 quired by philosophy. They are plausible. They have the merit 

 of logical continuity, and, excepting to those persons biased by 

 early subjection to contrary notions, they satisfy the " human 

 heart." There should be no natural repugnance to monism or to 

 pantheism, difficult as it is to associate the idea of truth and reality 

 with either or with the opposite of either. Speaking for myself, 

 I feel no repugnance to them. Thoy lend themselves to poetry ; 

 they appeal to the human heart. In Haeckel's own words, re- 

 ferring to something else, "such hereditary articles of faith take 

 root all the more firmly, the further they are removed from the 

 rational knowledge of Nature and enveloped in the mysterious 

 mantle of mythological poesy." The present resistance to them 

 may in time be turned into superstitious reverence for them ; for, 

 of all the philosophic doctrines brought down as lightning from 

 heaven for the guidance of plodding man, these seem most attract- 

 ive, and least likely to conflict with the conclusions of science. 



But can we give them belief ? Let us pass by the doctrine of 

 monism, with which science can not concern itself. What of the 

 corollaries ? Spontaneous generation, for example, has been the 

 basis of many experiments. Like the transmutation of metals, 

 it seems reasonable to philosophy. The one idea has been the 

 Will-o'-the-wisp of biology as the other has of chemistry. We 

 know absolutely nothing of how, if ever, non-life becomes life. 

 So far as we know, generation from first to last has been one 

 unbroken series "all life from life." We have no reason to be- 

 lieve that spontaneous generation exists under any conditions we 

 have ever known. We have likewise reason to believe that if it 

 exists at all we have no way of recognizing it. The organisms 

 we know have all had a long history. Even the smallest shows 

 traces of a long ancestry, a long process of natural selection, and 

 of many concessions to environments. We know of no life that 

 does not show such concessions. We know no creature that does 

 not show homologies with all other living beings whatsoever. So 

 far as this fact goes, it tends to show that all life is one. If this 

 is true, spontaneous generation, whatever it may be, is not one of 

 the ever-present phenomena of life. 



If life does now appear without living parentage, if organisms 

 fresh from the mint of creation now appear from inorganic matter, 

 they are so simple that we can not know them. They are so small 

 that we can not find them. They would be made, we may sup- 

 pose, each of a small number of molecules. If there is truth in 



