1892.] NEW-YORK MICROSCOPICAL SOCIETY. 3 



almost infinite sweep of the one class of objects, and the infi- 

 nitesimal dimensions and limited range of the other. Of what 

 significance are such magnitudes and distances as we can apply 

 our rules to, when neither the telescope nor the microscope has 

 penetrated to a final boundary? The fact is, we are overwhelmed 

 by the futility of our effort to follow out in imagination an endless 

 series, whether we look in one direction or turn about and look 

 in the other. 



The familiar identification of " the law which moulds a tear " 

 and that which " guides the planets in their course," may be paral- 

 leled in very various similitudes throughout nature, and the fact 

 that an object of investigation is minute in size, or comparatively 

 simple in structure, does not necessarily render the primal causes 

 of its being and actions any more easily discernible than they are 

 in the case of that which is grand and complicated. On the 

 contrary, complexity and multiplicity of parts have a tendency 

 to appear self-explanatory. Thus our own highly developed 

 body, with its numerous correlated and co-ordinated organs, is 

 regarded as less mysterious than is the apparently undifferentiated 

 and organless rhizopod, a seeming amorphous sample of the so- 

 called basal "life-stuff." So, too, the giant steam engine, which 

 impresses us mostly by its nearly irresistible power, never appears 

 as wholly inexplicable in its operation as does the simple living 

 current of protoplasm circling in a microscopic cell of Chara or 

 Anacharis. In reality, the vaster and more complex a mechanism 

 is, the more points it presents at which we are able to see the im- 

 mediate connection of cause and effect, and in following back 

 from one of these points to another we fancy we are explaining 

 the whole modus operandi. We realize the essential mysterious- 

 ness of the matter only when we reach an effect without an obvi- 

 ous cause, as we are sure to do if we pursue the subject persist- 

 ently and deeply enough. 



Thus all thorough study and research end, as they begin, with 

 a question. The interrogation-mark is, after all, the symbol of 

 the highest and latest human wisdom. My lecture, therefore, if 

 it pushes deep enough, is likely to close, as it opens, with the in- 

 quiry: IVhai is a Diatom ? 



Meanwhile, however, we may perhaps move our knowledge a 

 link or two along the chain of queries which constitutes the sci- 



