382 KANSAS ACADEMY OF SCIENCE 



All who are interested in this problem will at least agree that all 

 the activities of the mind, of the body as a whole, of each organ and 

 tissue, and of each protoplasmic cell may be grouped under one or the 

 other of a connected series of heads : 



1. Conscious activities. 



2. Habits. 



3. Subconscious activities. 



4. Instincts. 



The attitude of the evolutionist towards a consistent theory of de- 

 velopment of these four forms of activity and the exceeding impor- 

 tance of the life factor in them all will receive due attention in the 

 course of this discussion ; but the proper method to be employed in 

 studying any problem in which life is the chief factor demands im- 

 mediate consideration. 



The methods that have been employed in the solution of biolog- 

 ical problems are two in number, the mathematical method and the 

 life method. 



The mathematician is concerned with the investigation of the log- 

 ical consequences of certain exactly statable postulates or hyijotheses. 

 The method of the mathematician may be used with the greatest pro- 

 priety in all investigations in chemistry, physics, engineering, and 

 dynamical geology, for the factors in these subjects obey physical 

 laws and each cause is followed by its logical effect. 



In biology, on the contrary, the one who uses the method of the 

 mathematician can meet only with wrong results, for life obeys no 

 law other than its own highest good, and this cannot be stated in 

 mathematically exact terms. Life observes physical laws so far as 

 it is needful to do so to attain to its own best success in the struggle 

 for existence on earth and no further, and, therefore, where life inter- 

 venes, causes are not followed by their full, logical efiPects. 



Doctor Loeb, in his theory of tropism, says that an organism when 

 unequally stimulated is caused by the stimulus to so orient itself that 

 its parts are equally stimulated. He seems to mean that an organism 

 orients itself just as does the magnetic needle when under the influ- 

 ence of a parallel current of electricity. 



Doctor Jennings, of Pennsylvania University, has demonstrated in 

 a remarkable series of experiments that the amoeba, for example, does 

 not orient itself in accordance with the theory of tropism. In these 

 experiments Doctor Jennings found that the amoeba invariably 

 moves in accordance with an influence exerted from within, that trial 

 and failure are important factors in determining what it will do. 

 The external cause was not followed by its logical effect, for life in- 

 tervened and determined for itself the direction of motion. 



Doctor Hibben,of Princeton, says, in his "Problems of Philosophy," 



