April 5, 1895.] 



SCIENCE. 



383 



middle ground. ]\Iorc freedom is permitted 

 in other fields of thought. 



We may say that, since we know noth- 

 ing about it, we neither believe that the 

 planet Mars is nor that it is not inhabited, 

 but no such philosophic doubt is permitted 

 in biology. 



If a teacher of natural science were to 

 say he does not believe life is the outcome 

 of the physical and chemical properties of 

 protoplasm he would most surely be re- 

 ported as believing it is not the result of 

 these properties, and he would straightway 

 he branded a dangerous scientific heretic or 

 a weak brother of the faith, and Ms confes- 

 sion of ignorance would be put on record as 

 positive belief. 



This antipathy to philosophic doubt on 

 the problems of life is clearly due to the 

 dogmatism of the monistic creed, which 

 cannot admit the presence of anj- unjoined 

 links in our knowledge of nature. 



We might be indifierent to this intoler- 

 ance if it did not cause the most essential 

 characteristics of life to be ignored or pushed 

 into the backgi-ound. 



It is as true now as it was in Bacon's 

 day that: "Whoever, unable to doubt, 

 and eager to affirm, shall establish principles 

 proved, as he believes, . . and according 

 to the unmoved truth of these, shall reject 

 or receive others, . . he shall exchange 

 things for words, reason for insanity, the 

 world for a fable, and shall be unable to 

 interpret/' 



The essential characteristic of life is fit- 

 ness. 



A living organism is a being which uses 

 the world around it for its own good. 



I, for one, am unable to find, in inorganic 

 matter, any germ of this wonderful at- 

 trilnite. 



It is po.ssible that after chemistry lias 

 given us artificial protoplasm this may be 

 shaped, bj' selection or some other agency, 

 into persistent adjustment to the shifting 



world around it, and that it may thus l)e- 

 come alive. 



Everything is possible in the unknown, 

 but why should we believe anything on the 

 subject until we liave evidence ? 



Of one thing we maj' be sure. The arti- 

 ficial production of protoplasm would not 

 be a solution of the problem of life. The 

 nature of the problem must be grasped in all 

 its length and breadth, with all its diffi- 

 culties, before we can hope to solve it. 



Many biologists have sought to solve it by 

 transforming Huxley's carefully guarded 

 statement that protoplasm is the physical 

 basis of life into the dogma that life is the 

 sum of the physical properties of protoplasm. 



Life cannot go on without food, and we 

 may say with propriety that bread is the 

 staff of life, but the agency which shapes the 

 food into the specific structure of an organ- 

 ism exquisitely adapted to the conditions of 

 the M'orld around it is to be sought some- 

 where else than in the properties of bread. 



One of the distinctive characteristics of 

 this organizing agency is that it may exist 

 in a germ without any visible organization. 

 Another is that, so far as we know, it has 

 been handed down, in an unbroken line, 

 from the oldest living things, generation af- 

 ter generation, to the modern forms of life, 

 and that it has leavened the whole hump 

 of living matter. 



While we know nothing of its nature or 

 origin, and must guard against any un- 

 proved assumption, there seem, from our 

 present standpoint, to be insuperable objec- 

 tions to the view that this agency is either 

 matter or energy. While we know it only 

 in union Avith protoplasm, it would seem 

 that, if it is matter, it must, long ago, have 

 reached the minimum divisibile. If it is en- 

 ergy, or wave motion, or perigenesis of 

 plastidules, it is hard to understand why it 

 has not l)ecn dissipated and exhausted. We 

 know that it exists, and this is in itself a 

 fact of the utmost moment. 



