286 PHYSICAL EXPRESSION. 



to the fact of their being twins, owing to all the 

 events of intra- uterine life having been similar to 

 each. Is it not probable that the same cause is 

 connected with the similarity of the series of 

 trophic actions, and the series of kinetic actions ? 

 It is possible to describe walking and speaking in 

 terms of a series of movements. 



This suggests that " If two or more living 

 subjects be co-nourished during the period of 

 development they will tend to ' similar proportional 

 development' and 'similar series of kinetic 

 actions/ " 



Let us try and see exactly what it is that is 

 thus compared. 



The series of trophic actions in each subject 

 corresponds, or is similar in the same periods of 

 growth ; only observation can prove this. Observa- 

 tion shows in Arthur and John that growth is 

 similar in kind, and in quantity, in each successive 

 period of time ; it is the attributes time, quantity, 

 and kind of growth that are similar. 



Summary. Any property or function may be 

 described as having the three attributes time, 

 quantity, kind. This may be illustrated with 

 regard to growth, or trophic action ; and also with 

 regard to movement, or kinetic action. 



The attribute time includes the moment of action, 

 frequency, duration of the active appearance, and of 

 the quiescence or disappearance of the function. 

 Time is the only attribute of totally dissimilar 

 functions that can be directly compared. As to 

 quantity, this is measurable, but some unit of 



