THE president's ADDRESS. 243 



hear a description of an arrangement by which researches by means 

 of polarised light may be much facilitated, and rendered, in some 

 respects, much more accurate. For the exquisite beauty of the 

 results which Mr. Field's method is capable of exhibiting, I can 

 most thoroughly v.ouch, and to some extent I believe you will 

 speedily have the opportunity of judging for yourselves.* 



It is an old story that Alexander wept because he had no more 

 worlds to conquer. Truly it must be a long time ere the Micro- 

 scopist can have cause to weep on any such account. No field of 

 microscopical research is yet fully explored, much less exhausted. 

 Further search finds everywhere something fresh. New methods 

 of illumination are constantly showing what has been already 

 seen in some new light, and some new interpretation is being sug- 

 gested. New methods of preparation or research exhibit plainly 

 what before was obscure or altogether invisible. And when all is 

 done, it still seems that the Microscopist may almost create, as it 

 were, new worlds for himself. This consideration — this vague 

 suggestion — brings me to a subject upon which I wish to take the 

 opportunity of saying a few words to you. The subject to which 

 I allude is that which ordinarily goes by the designation of " spon- 

 taneous generation." But surely a more obvious misnomer was 

 never applied to any series of phenomena, imagined or observed. 



Now a belief in the so-called spontaneous generation of living 

 creatures is of very ancient date. But the earlier ideas on the 

 subject can only be regarded as so many fanciful interpretations of 

 imperfectly observed phenomena. 



Of late years, however, by the aid of the microscope, some of 

 the questions involved have been repeatedly submitted to something 

 approaching to precise investigation. And the results obtained, 

 although by no means final, are yet very suggestive, and full of 

 interest. 



It has been clearly established that all the higher animals and 

 plants derive their origin from similar and previously existing organ- 

 isms. Upon this point there is no longer any possibility of dispute. 



But with regard to the very lowest forms of life — the Bactei-ia, 

 Vibrios, Monads, and such like — it is somewhat different. Their 

 mode of origin still aj^pears to be at best but doubtful. Two diame- 



* See Paper by Mr. Field on the " Ratio-Miero-PoLiriscope," at page 215. It 

 is only rif^ht to add that Mr. Hislop has already exhibited a somewhat different 

 and simple arrangement, devised by himself, by wliich similar advantages are 

 obtained. A full description was read at the Meeting on the 27th of August, 

 but the instrument itself was shewn long previously. See p. 225. 



