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SCIENCE 



[N. S. Vol. XXXIII. No. 859 



chemicals, so that the condition under which 

 entelechy comes into play is always realized. 

 We may therefore expect its action at any 

 step in our work; we must be prepared at all 

 times to find the same physical configuration 

 giving rise now to one result, now to another ; 

 we can have no confidence that when two ex- 

 periments give different results, it will be pos- 

 sible to find an experimental cause for this 

 difference. 



Doubtless there are investigators who can 

 persuade themselves that they really believe 

 this sort of thing, and yet who can continue 

 hopefiilly their hopeless task of trying to dis- 

 cover experimentally the conditions that de- 

 termine what happens — just as there are per- 

 sons who assert that they believe certain 

 orthodox religious doctrines and yet live 

 cheerfully the life of the worldly. But for 

 one who takes his experimental work seri- 

 ously and who has use for theories only as 

 theories of practise, the acceptance of such a 

 doctrine can not fail to profoundly change his 

 work and his attitude toward his work." It 

 takes away the guiding principle on which 

 every step of his work is based. 



Thus a doctrine which holds to consistent 

 physical determinism in the inorganic sci- 

 ences and rejects it for biology makes a tre- 

 mendous difference in principle between the 

 two fields; a difference big with practical re- 

 sults. I believe that to most working investi- 

 gators of biology the question of vitalism 

 means the question whether there is such a 

 difference, and it appears unfortunate that 



" Of course there would still be work for the 

 biologist. Descriptive and observational work 

 would be little affected. The biologist could sub- 

 stitute "entelechy" for "god" or "provi- 

 dence " or " nature ' ' in the pious expositions of 

 the naturalists of two generations ago, and de- 

 vote himself to showing the wonderful and un- 

 fathomable ways of entelechy. If of an incurably 

 analytic turn of mind he could even examine the 

 limitations which the physical conditions place 

 upon entelechy: and perhaps make a catalogue and 

 classification of the various results produced by 

 entelechy from a given physical configuration. It 

 is the principles, methods and objects of experi- 

 mentation that would be changed. 



this question should be obscured by confusing 

 it with the (for the working investigator) 

 relatively inconsequential question as to 

 whether anything happens in living things 

 that doesn't happen in those not alive. 



H. S. Jennings 

 Johns Hopkins University, 

 May 16, 1911 



THE application OF THE METHOD OF LEAST 

 SQUARES 



To THE Editor of Science: It would, I 

 think, be interesting and valuable to have a 

 consensus of opinion from both astronomers 

 and physicists as to the limits within which 

 the application of the method of least squares 

 is permissible. This method is used widely 

 by astronomers and but rarely by physicists. 

 Moreover, I believe most physicists would 

 hesitate to push the application of the method 

 as far as is commonly done by astronomers. 



To take a concrete ease: During the discus- 

 sion, that followed the Saturday afternoon 

 symposium at the recent general meeting of 

 the Auierican Philosophical Society, one point 

 under discussion was whether or not the prin- 

 ciple of relativity requires the abandonment 

 of the concept of the ether. The writer men- 

 tioned as an experimentum crucis the possi- 

 bility of detecting an ether-wind by measuring 

 the speed of light in a single direction and 

 over a path which for its greater part lay 

 remote from the surface of the earth, thus 

 avoiding a limitation of the Miehelson-Morley 

 experiment. It was suggested that if the 

 measurement of the speed of light by Homer's 

 method could be carried out with sufficient 

 accuracy, and at two such times that the light 

 would have to travel with and against the 

 proper motion of the solar system, such an 

 ether-wind might be observed. It was pointed 

 out that the difference of time to be expected 

 would be of the order of one fifteenth of a 

 second. Some doubt, was expressed as to 

 whether this accuracy was yet attainable in a 

 difficult measurement of this nature. 



To this Professor Pickering replied that a 

 large mass of such data was already in the 

 possession of the Harvard Observatory, and 

 had been discussed and reduced with this very 



