March 21, 19U2.J 



SCIENCE. 



445 



1. Among the things of wliich he hopes 

 to, some day, give an account, the em- 

 hryologist must include m.en tvho think 

 and act. 



Of all the facts that are made known 

 by experiments upon the generation and 

 regeneration of living things, the one we 

 are least likely to doubt is the existence of 

 the experimenter. We may question the 

 value of his results, but we are not likely to 

 doubt that he did, or tried to do, or thought 

 that he did, the things he describes. 



The experimental embryologist comes 

 out of an egg, and he must himself be in- 

 cluded among the facts of development 

 which are the object of the observations 

 and experiments and reflections by which 

 he seeks to account for the production of 

 living things out of eggs. 



Since some of the things that come out 

 of eggs observe, and reflect, and try ex- 

 periments, the production of living things 

 out of eggs cannot be adequately explain- 

 ed, or accounted for, unless the production 

 out of eggs of things that observe and re- 

 flect and try experiments is also explained 

 or accounted for. To make good its claims 

 to our favorable consideration, embryolog- 

 ical science must undertake to account, in 

 good time, for minds, in exactly the same 

 sense of the word as that in which it un- 

 dertakes to account for bodies and brains. 



2. The intellectual powers by the aid of 

 which we make scientific discoveries come 

 out of eggs. 



Honesty, and independence, and accu- 

 racy, and determination, and good sense, 

 are essential to sound progress in scientific 

 discovery. The investigator who is no 

 biologist may take his own honesty, and 

 independence, and accuracy, and determin- 

 ation, and good sense, for granted, as 

 ultimate facts that do not need to be ac- 

 counted for. But honest men, and accu- 

 rate men, and independent men, and reso- 

 lute men, and men with good judgment, 



all come out of eggs, and the embryologist 

 cannot forget that they are among the 

 natural phenomena of which he hopes to, 

 some day, give a scientific account. 



The final and decisive test of any ex- 

 planation of the generation of living 

 things out of eggs is the account which it 

 gives of the origin and significance of our 

 ability to observe and refiect and try ex- 

 periments; for no scientific discovery is 

 worthy of confidence, unless our intellect- 

 ual means for finding out things are sound 

 and trustworthy. Thus, the progress of 

 embryological science must bring us 

 around, sooner or later, by a new path, to 

 the old question : What is science ? What 

 is it to know a thing? It may be that we 

 shall find, from this new point of view, 

 something in knowledge that has been neg- 

 lected, or too little considered, and we may 

 thus be helped to better notions. 



3. No embryologist can, knowingly, hold 

 any opinion which excludes the possibility 

 of embryological science. 



Each student of science must devote 

 himself to some small part of the realm of 

 nature in order to make progress. We 

 study simple phenomena in the hope that 

 we may pass, in time, to those that are 

 more complex and difficult. If astrono- 

 mers, and chemists, and students of phys- 

 ics, and embryologists, and zoologists, see 

 fit to temporarily lay aside the natural his- 

 tory of mind, as a problem which does not, 

 for the time, interest them, nor seem to 

 concern them, or as something that is too 

 hard for them, no one can doubt their wis- 

 dom. But if their methods and results 

 lead them, or seem to lead them, to the 

 conclusion that what has thus been tem- 

 porarily laid on the shelf can never be 

 taken down from the shelf, is it not clear 

 that there has been a mistake somewhere? 

 Any method of embryological research 

 which leads to the conclusion that there is 

 a ' chasm ' which is ' intellectually impass- 



