78 University of California PxMications in Zoology [Vol. 19 



While some conditions can be duplicated in a laboratory it is impos- 

 sible to reproduce the entire environmental complex, unless it be in 

 the case of a culture of protozoa or organisms like rotifers. This whole 

 matter has been discussed by Hargitt (1912, pp. 51, 52) and one can 

 hardly do better than quote him. 



What right has one to assume that the reactions of an animal taken rudely 

 from its natural habitat and as rudely imprisoned in some improvised cage 

 are in any scientific sense an expression of its normal behavior either physical 

 or psychical! Is it within the range of the calculus of probability that con- 

 clusions drawn from observations made upon an animal in the shallow confines 

 of a finger-bowl, but whose habitat has been the sea, are trustworthy? . . . 

 laboratory appliances are indispensable. But at the same time it must be 

 recognised that they are at best but artificial makeshifts whose values, unless 

 checked by constant appeals to nature, must be taken at something of a dis- 

 count. This must be especially the case with higher organisms. It seems to 

 the writer that until one has been able to place his specimens under conditions 

 approximating the natural, or has at least brought them to a state of semi- 

 domestication ... he has small right to dogmatize as to conclusions or to make 

 such conclusions the basis of so-called laws of behavior. 



Burckhardt (1910, p. 200) writes as follows with regard to the arti- 

 ficial conditions that apply in experiments in the diurnal movement: 



Kann eine Gliihlampe das Tageslicht ohne weiteres ersetzen? Haben die 

 stark divergenten Strahlen einer so nahen Lampe dieselbe Wirkung, wie die 

 parallelen der Sonne? . . . Darf man vom plotzlichen Andrehen einer Lampe 

 dieselbe Wirkung erwarten, wie vom allmahlichen Aufgehen und Aufsteigen 

 des Tagesstirns? . . . Mir personlich scheint einstweilen immer noch, aus- 

 sichtsvoller als die Sisyphusarbeit, im Laboratorium naturliche Bedingungen 

 herzustellen, sei die Beobachtung der mannigfaltigen Experimente, die die 

 Natur in den naturlichen Wasserbecken ausstellt. Haben wir das erschopfend 

 getan, werden uns unsere Kenntnisse auch die Sisyphusarbeit leichter machen. 



The statements of Longley (1917, p. 550) may appropriately be 

 referred to in this connection, where he mentions the color changes 

 shown by fishes in tanks as compared with animals under natural 

 surroundings. 



There is no doubt that the questions asked by Hargitt and Burck- 

 hardt are pertinent. The attitude revealed by such questions will 

 probably lead to another : Of what use, then, is the method of labora- 

 tory experiment? .The answer will depend largely upon the end 

 that the experimenter has in view. If he is desirous of finding, for 

 instance, what organisms can do, or how sensitive they are to varia- 

 tions in outer factors, the laboratory method is the only one to use. 

 But when the laboratory results are to be used as explanatory of habits 

 in nature it must be said that the experimental method is of little use 

 if it is followed without regard for its obvious limitations. 



