October 22, 1909] 



SCIENCE 



563 



unchanging law; yet nature is intricate, pro- 

 foundly intricate, and its processes interact 

 beyond man's faculty of perception. 



How the idea of complexity in nature is 

 important may best be seen in its application 

 to cause, condition and efFect, the three essen- 

 tial topics of every theory. According to this 

 conception, one effect may be the result of 

 several causes. For instance, as Professor 

 Crosby pointed out some years ago,' eskers 

 may be partly of subglacial and partly of 

 superglacial origin, and a single esker may be 

 both in different portions of its course. The 

 hydrocarbons, in their various occurrences, do 

 not always satisfy the view entertained by 

 some geologists, that they have had an organic 

 source. Hence it is probable that they (the 

 hydrocarbons) are like effects to be ascribed 

 to different causes. Moreover, to say that, 

 inasmuch as we observe a certain deposit to 

 be forming to-day by a certain process, " it is 

 therefore a legitimate theory that all similar 

 deposits have the same origin," ' is unsafe 

 reasoning. Because limestone is now in the 

 making as an organic deposit, all limestone 

 has not necessarily been so derived. Multi- 

 plicity of causes, then, must be taken into con- 

 sideration by the theorist. 



On the other hand, while the cause may be 

 single, the conditions under which it acts may 

 be so various that the effects are manifold. 

 If the circumstances of origin are widely dif- 

 ferent, interpretation of the results is not so 

 difficult as it is when these conditions are hard 

 to discriminate. Thus, a theoi-y of wind- 

 worn sand should have regard for the com- 

 position of the sand; the size, weight, specific 

 gravity, hardness and cleavage of the grains; 

 and the prevailing wind velocity. So, too, any 

 exposition of the origin of phenocrysts in 

 igneous rocks should be developed with due 

 heed for variations in the acidity and basicity 

 of magma and of country rock. Consequently, 



' W. 0. Crosby, "Origin of Eskers," Am. Geol., 

 XXX., p. 2. 



' H. L. Faibchild, " Geology under the New 

 Hypothesis of Earth-origin," Am. Geol., XXXIII., 

 p. 107. 



multiplicity of conditions is also to be allowed 

 for in elaborating a theory. 



Thus, in the intricate system of nature, 

 similar products may be the outcome of dif- 

 ferent causes, and unlike products may result 

 from 0716 cause, in each case the causes working 

 under varied conditions. Although there are 

 many other relations between cause, condition 

 and effect, these two are especially emphasized 

 here because they are most easily overlooked. 



Summarizing — theory and hypothesis too 

 often suffer from the mistake, first, of over- 

 rating the importance of some one particular 

 cause or condition, and, second, of extending, 

 more broadly than is legitimate, the applica- 

 tion of this factor. These fallacies are in 

 large part due to a failure to realize the ex- 

 treme complexity of the relations between 

 cause, condition and effect. 



To avoid misunderstanding and to give a 

 theory real value, we must assign to it definite 

 limits, beyond which criticism should not 

 reach. Be discreet in generalization, is good 

 counsel. Fred. H. Lahbe 



Hakvabd Univebsitt, 

 January 4, 1909 



THE BEHAVIOR OF A SNAKE 



Several years ago, while Mr. Lester and 1 

 were sauntering along a country road near 

 Newnan, Ga., a commotion was heard in the 

 dry leaves along the side of the road. On 

 quietly entering the underbush, it was noticed 

 that the noise was caused by a struggle be- 

 tween a coach-whip snake (Zamiens fiagellum 

 fiagellum Shaw) and a lizard that was un- 

 known to me. The snake was about four feet 

 long; the lizard less than a foot. They were 

 not fighting; the snake was trying to make a 

 meal of the unmanageable lizard. Fre- 

 quently the lizard escaped from the snake. 

 Then would follow a chase resulting in the 

 recapture of the lizard. The snake invariably 

 caught the lizard by the bodj'. I knew that, 

 if the snake were to capture the lizard by the 

 tail, the lizard would break off the tail and 

 escape. The snake, behaving as though aware 

 of this, attracted my attention and caused me 

 to remain and study its movements. 



