50 THE QUANTITATIVE METHOD IN BIOLOGY 



On the other hand, they look upon this method as being an 

 impossibility in descriptive science, or a fearful something 

 because of the long labour required for the measurement of the 

 properties of animals and plants. It seems as if they did not 

 realize that, for instance, the determination of the duration ^ of 

 the three periods of the contraction of a muscle and the measure- 

 ment of the relations between fatigue, temperature, intensity 

 of the stimulus, etc., and these periods require very long and 

 exceedingly deUcate work, and that numerous experiments are 

 needed to establish one figure. 



The aim of the quantitative method in descriptive science is 

 not only to describe exactly the properties of the species and to 

 make an inventory of the forms of hfe. This is important enough 

 in itself, but there is more. It is difficult to obtain exact data 

 about the development and the anatomy of animals and plants 

 as long as the observed facts are described by means of mere 

 terms. It is stiU more difficult to discover the origin of species 

 and their phyletic relations without an exact knowledge of the 

 investigated species. This can only be obtained by comparing 

 their characteristic figures with the figures of other species. 

 The object of the quantitative method is, in general, the exact 

 description of the living objects. 



The HAECKELIAN method has been, for more than forty 

 years, an important instrument of progress. It is, however, 

 open to certain criticism. (See § 50.) Among other things, it has 

 diverted attention from the quantitative investigation initiated 

 by QUETELET, MENDEL and also by DARWIN. There- 

 fore the HAECKELIAN method, in spite of its high merits, 

 does not enable us to get to the bottom of the biological prob- 

 lems. It cannot advance our knowledge beyond a certain 

 limit. 



^ Expressed, for instance, in hundredths of a second. 



