ROTIFERA. 29 



Time was, and not very long ago, in this country, w^hen that term. 

 Microscopical Anatomy, was almost regarded as synonymous with the 

 anatomy of the imagination : but the numerous and highly important 

 discoveries which have been made and confirmed by observers in 

 almost every European state, by means of the greatly improved mi- 

 croscopes of the last ten years, have placed the value, the indispensa- 

 bility, of that instrument to the anatomist, beyond the necessity of 

 vindication. 



Some scepticism may be natural and pardonable, when the anatomy 

 of an animalcule XdVo of ^ ^^^^ "^ diameter is attempted to be 

 demonstrated : but trace it to its source, and you will find such 

 incredulity to be essentially based, not merely on distrust in our 

 means of observation, but in the difficulty of adequately conceiving 

 the relations of size. Just ideas of these relations are essential to the 

 acceptance and full appreciation of the discoveries which have extended 

 for us the bounds of space ; and I will ask permission to quote the 

 words of one of our old philosophers, which bear directly on this 

 subject, and, expressing a noble confidence in intellectual progress, 

 shed a prophetic gleam upon the present impi-oved powers of pene- 

 trating space. 



"In consistency, I suppose some bodies to be harder, others softer, 

 through all the several degrees of tenacity. In magnitude, some to 

 be greater, others less, and many unspeakably little. For we must 

 remember that, by the understanding, quantity is divisible into 

 divisibles perpetually. And therefore, if a man could do as much 

 with his hands as he can with his understanding, he would be able to 

 take from any given magnitude a part which should be less than any 

 other magnitude given. But the omnipotent Creator of the world can 

 actually from a part of any thing take another part, as far as we by 

 our understanding can conceive the same to be divisible. Wherefore 

 there is no impossible smallness of bodies. And what hinders but 

 that we may think this likely ? For we know there are some living 

 creatures so small that we can scarce see their whole bodies. Yet 

 even these have their young ones ; their little veins and other vessels, 

 and their eyes so small as that no microscope can make them visible. 

 So that we cannot suppose any magnitude so little, but that our very 

 supposition is actually exceeded by nature. 



" Besides, there are now," (the book was published in 1655) " such 

 microscopes commonly made, that the things we see with them appear 

 a thousand times bigger than they would do if we looked upon them 

 with our bare eyes. Nor is there any doubt but that, by augmenting 

 the power of these microscopes (for it may be augmented as long as 

 neither matter nor the hands of workmen are wanting), every one of 



