445 THE CANADIAN NATURALIST. [BeC. 



connected with the supply of all human necessities and comforts. 

 But this knowledge is not merely useful, it is also elevating and 

 interesting in the highest possible degree ; and this I will proceed 

 to show as far as I can in the brief limits to which I must confine 

 myself, by seeking in the three great kingdoms of nature some 

 practical illustrations of the truth of these assertions. 



The animal world, from which we may take our first illustra- 

 tion, presents, from its lowest to its highest forms, a series of 

 organic structures progressing with almost imperceptible gradation 

 in perfection of development and complexity of organization. 

 Amongst the simplest of its representatives are the Protozoa, 

 the great majority of which are too small to be distinguished 

 without the aid of the microscope. They are graphically 

 described by Dr. "Wm. B. Carpenter as consisting of " seemingly 

 structureless jelly." They perform those vital operations which 

 we are accustomed to see carried on by an elaborate apparatus 

 without any special instruments whatever ; a little particle of 

 apparently homogeneous jelly changing itself into a greater variety 

 of forms than the fabled Proteus, — laying hold of its food without 

 members, swallowing without a mouth, digesting without a 

 stomach, appropriating its nutritious material without absorbent 

 vessels or a circulatory system, moving from place to place without 

 muscles, feeling (if it has any power to do so) without nerves, 

 multiplying itself without eggs, and not only this, but, in many 

 instances, forming shelly coverings of a symmetry and complexity 

 not surpassed by those of any molluscous animal. And yet 

 these creatures have performed, and are still performing, one of 

 the chief parts in the history of this globe. With them, we 

 arrive at that mysterious border-land which divides, and yet 

 seemingly blends, the organic and inorganic world; where we find 

 arising the simplest vegetable and animal structures scarcely 

 distinguishable from each other, and beyond which we cannot 

 proceed in our search for the beginning of life. Yet the earnest 

 student when examining them feels with more than ordinary 

 intensity the profound mystery of life, and will continue to 

 investigate the phenomena they present in eager hope of new 

 revelations. But the Protozoa have not ungenerously left without 

 reward the researches made in their behalf. They have presented 

 to man's astonished sight objects of marvellous beauty in the 

 form and structure of the microscopic shells of many of them. 

 They have also enabled him to obtain enlarged conceptions 



