264 THE RELATIONS OF BIPOLARII'Y AND BILATERALITY 



an amount of which no definite estimate could be made that 

 would be sufficient to separate the animal in question either 

 from fishes on the one hand or from reptiles on the other. 



Now this is the way in which naturalists proceed, step by step, 

 balancing, through all the intimate details of an organization, 

 the several features which are opened to their eyes by the help of 

 the dissecting knife and the microscope. Of course you must see, 

 even from this slight sketch, that it would be a work of weeks, and 

 even months, if I were to undertake to go through even the prin- 

 cipal groups of the animal kingdom, to say nothing of the lesser 

 communities of relations, such as exist among specific characters. 



The case of the Lepidosiren is one among many that are just 

 as remarkable and indeterminable, if one wishes to make defi- 

 nite, sharp boundary lines, like checker-board work, between all 

 the various groups of animals. But the relations of Nature are 

 not of this kind; the square, rule, and compass and the checker- 

 board formulae are but the expressions of the limitations of 

 human comprehension among the untutored ; but as we advance 

 in the knowledge of our own minds, and by degrees take in the 

 immense breadth of intellect with which man is endowed, we 

 gradually come to a better understanding of the workings of 

 that greater mind which originally conceived, and gave us birth. 



We have already had some glimpses of the order of things 

 which reigns among the animal groups; we have seen that the 

 principle of life is the expression of a grand idea which shines 

 forth in all Organic Nature ; we have seen that from and upon 

 this idea is erected the idea of form in a twofold relation, that 

 of the animal physiognomy on the one hand, and that of the 

 plant on the other ; but yet related in such a way that a concep- 

 tion of their difference would seem to be beyond the power of 

 the finite human mind, and we fain would come to the conclu- 

 sion that the difference is but one of degree. 



For the animal kingdom we have traced an idea of progres- 

 sion which is expressed in several ways ; and these ways are seen 

 to refer more or less to each other, as if they were but the collat- 

 eral branches of one main line. At the outset the principle of 

 life takes on an outward form in the bipolarUy of the egg. This 



