EXPERIMENTS WITH LIVING HUMAN BEINGS. 613 



The elements of error in experimenting with inanimate objects 

 were indicated, in a general way, by Bacon, under the strange headings 

 " Idols of the Tribe," " Of the Den," " Of the Forum," " Of the The- 

 atre"; and later writers on evidence and the principles of science have 

 repeated or assumed the Baconian formulas ; but the special elements 

 of error in experimenting with living human beings have escaped con- 

 scious and exhaustive analysis. To have formulated these elements of 

 error much sooner than the present time would have been quite impos- 

 sible, for our knowledge of the involuntary life — one of the most im- 

 portant factors — was far too limited. 



The science and art of experimenting with living human beings is 

 indeed now in precisely the same state as the general philosophy of in- 

 duction prior to the time of Bacon. Before the era of the Baconian 

 philosophy, indeed in all eras, men had instinctively employed the in- 

 ductive method, but the principles of that method had never been for- 

 mulated ; consequently, when philosophers reasoned or attempted to 

 reason on the subject, they almost always went wrong. The philosophy 

 of Bacon applies only to inanimate nature ; of the art of seeking truth 

 through experiments on living human beings — of the six sources of 

 error in all such experiments and the means of guarding against them 

 — he knew nothing, and evidently suspected nothing ; and that branch 

 of philosophy — of such vast import in biological investigations — has re- 

 mained to this day unstudied and almost unthought of; hence, although 

 some experimenters are saved through their instincts, others — and those 

 the very ablest scientific geniuses of the age — never attempt to reason 

 on the subject without falling into serious error. 



In experimenting with living human beings there are, as above 

 stated, just six sources of error, all of which are to be recognized and 

 systematically and, if possible, also simultaneously guarded against if 

 our results are to command the confidence and homage of science. To 

 be guilty of overlooking, in any research, even one of these six possi- 

 bilities of error, is to be guilty of overlooking all, and practically to 

 vitiate all the results of our labors. 



These six sources of error are as follows : 



First Source of Error : The phenomena of the involuntary life 

 in both the experimenter and the subject experimented on. — Under this 

 head are embraced trance, with all its manifold symptoms, and all the 

 interactions of mind and body that are below the plane of volition or 

 of consciousness or of both. Without a knowledge of this side of 

 physiology, scientific experimenting with living human beings is impos- 

 sible. It is a want of this knowledge that makes most of the experi- 

 ments of scientific men in this department during the past century so 

 unsatisfactory and so ludicrous. 



SEC0^^) Source of Error : Unconscious deception on the part 

 of the subject exjyerimented on. — This unconscious deception comes 



