152 FRAGMENTS OF SCIENCE. 



figures the molecules from which they directly spring ; with 

 him there is but a step from the atom to the organism. 

 The other discerns numberless organic gradations between 

 both. Compared with his atoms, the smallest vibrios and 

 bacteria of the microscopic field are as behemoth and levia- 

 than. The law of relativity may to some extent explain 

 the different attitudes of these two men with regard to the 

 question of spontaneous generation. An amount of evi- 

 dence which satisfies the one entirely fails to satisfy the 

 other; and while to the one the last bold defence and start- 

 ling expansion of the doctrine will appear perfectly conclu- 

 sive, to the other it will present itself as imposing a profit- 

 less labor of demolition on subsequent investigators. 1 



I trust, Mr. President, that you — whom untoward circum- 

 stances have made a biologist, but who still keep alive your 

 sympathy with that class of inquiries which Nature intend- 

 ed you to pursue and adorn — will excuse me to your breth- 

 ren if I say that some of them seem to form an inadequate 

 estimate of the distance which separates the microscopic 

 from the molecular limit, and that, as a consequence, they 

 sometimes employ a phraseology which is calculated to mis- 

 lead. "When, for example, the contents of a cell are de- 

 scribed as perfectly homogeneous, as absolutely structure- 

 less, because the microscope fails to distinguish any struct- 

 ure, then I think the microscope begins to play a mischiev- 

 ous part. A little consideration will make it plain to all 

 of you that the microscope can have no voice in the real 

 question of germ-structure. Distilled water is more per- 

 fectly homogeneous than the contents of any possible or- 

 ganic germ. What causes the liquid to cease contracting 

 at 39° Fahrenheit, and to expand until it freezes ? It is a 

 structural process of which the microscope can take no 

 note, nor is it likely to do so by any conceivable extension 



1 A resolute scrutiny of the experiments, recently executed with 

 reference to this question, is sure to yield instructive results. 



