THE VALUE OF ECOLOGICAL SURVEYS 27 



of the normal order of nature by man, and each 

 should be studied scientifically. But the science 

 of pathology has developed best as a study of the 

 disturbances of normal processes and is interpreted 

 primarily in terms of the normal ; and the artificial 

 should be similarly interpreted the natural being 

 the basis to which all standards must be referred. 

 A comparison may also profitably be made be- 

 tween natural conditions and the physiological and 

 vital optima of organisms and to the responses which 

 are made with departures from such conditions. 

 Similar comparisons should be made in the study 

 of the responses of aggregations and associations 

 in natural environments and departures from them. 

 No matter how much we learn, the normal must 

 remain as the ideal, and all departures from and dis- 

 turbances of such conditions must be interpreted in 

 terms of this fundamental unit. 



To study disturbed, artificial, and " pathological " 

 conditions, without an adequate knowledge of the 

 normal and original conditions of both the organ- 

 isms and the environment, is an attempt to interpret 

 the abnormal and artificial in terms of itself, rather 

 than in terms of the normal. If, however, the normal 

 is no longer preserved, then its nearest approach 

 should be studied, but with all the more care and 

 caution. With a proper understanding of the 

 normal, the disturbances made by man will be capa- 

 ble of interpretation in an orderly sequence strictly 

 comparable to that found in the original and natural 

 conditions. The cutting down and washing of the 



