A STUDY OF LOWER LIFE. 67 



parts are not commonly replaced in higher animals, for the 

 reason that the loss has entailed a separation from other 

 parts possessing no inherent powers of reproduction within 

 themselves, but deriving their sustenance and life as did the 

 lost parts from the entire, connected, and interdependent 

 system. 



The process of growth and the harmonious relation of 

 organs and parts observed in hydrae and in most other living 

 beings, suggests, as a final feature worthy of note, the con- 

 sideration of what is implied in the growth and increase of 

 living organisms generally. The body of the hydra was seen 

 at an early stage of our investigation to be composed of defi- 

 nite layers or tissues, and these tissues again to be made up 

 of minute elements or " cells." The general growth of the 

 hydra, therefore, in reality means the increase of each of 

 its minute parts, and when we reflect on the law of growth 

 thus evolved, we may be puzzled to account for or explain 

 the nature of the mysterious power which is seen to operate 

 in controlling and directing in so remarkable a manner the 

 functions of this humble organism. In the hydra, then, as 

 representing a single organism, or still better in the 

 zoophyte, which consists of a colony of animals, numbering 

 it may be many hundreds, united in a close structural rela- 

 tionship, or in the bodies of higher animals still, we find 

 the principle of the perfect co-operation of many different 

 parts to one harmonious end, namely, the maintenance 

 of the organism, beautifully exemplified. 



In most of the grave affairs of life, man strives to 

 secure the co-operation of his fellows, but humanity, unfor- 

 tunately for the success of man's schemes, exhibits many little 

 weaknesses and failings ; and the common tendency of one 

 mind to assert its supremacy over the others may result in 

 the entire demolition of the co-operative idea. Man might, 

 therefore, well strive to imitate the unselfish union of aims 

 and ends which a zoophyte-colony exemplifies, or which the 

 vital mechanism of his own tissues illustrates. When the 

 political economist shall have succeeded in inaugurating a 



