102 THE VICTORIAN NATURALIST. 



DIATOMS: NOTES ON THEIR COLLECTION, 

 CLEANING AND MOUNTING. 



By Henry Grayson. 



(Read before the Field Naturalists Club of Victoria, 12th 

 September, 1892.,) 



The subject before us to-night is a formidable one, and one I 

 have found it difficult to approach without a feeling of diffidence. 

 So much has been said and written about diatoms that now, in 

 certain quarters, one is almost afraid to mention the name, lest 

 the not very complimentary term " diatomaniac " should be 

 applied to one. I am not going to deny that valuable time is 

 often wasted upon them — in fact, I do not know that I am wholly 

 innocent in this respect myself. So much conceded, we must all 

 admit that the possessor of a microscope has a perfect right to pur- 

 chase a slide of diatoms if he chooses, and spend an hour or two 

 now and again in trying or testing first one and then another of 

 his objectives upon it. Time so spent need not be regarded as 

 wasted; for to properly display objects under a microscope is to 

 a certain extent an art, for it not only demands dexterity in 

 the manipulation of the instrument and its appliances, but also 

 requires knowledge of what sort of illumination is best suited to 

 the objects to be examined. Dr. Dallinger very truly says:—" For 

 learning the manipulation of the instrument no class of objects 

 are as suitable as diatoms. They are also an excellent means of 

 training the eye to appreciate critical images." 



Having learnt so much, it would be extreme folly to advance 

 no further. Much remains to be done even in connection with 

 the study of diatoms. This particular study may not be so 

 " absorbing " as the study of the sponges, for instance ; but, con- 

 sidering the number of years naturalists have been working at 

 both sponges and diatoms, the amount of information "squeezed" 

 out of diatoms will bear favourable comparison with that obtained 

 from sponges. Moreover, the time and patience given by a 

 devoted band of enthusiasts — I will not term them " diato- 

 maniacs " — has not been by any means lost to workers in other 

 departments of scientific research. We are entirely indebted to 

 diatomists for the splendid results recently achieved in the purely 

 optical part of microscopical work. The demand for more and 

 yet more " angle " and " light" has resulted, not so much as was 

 supposed in the ultimate resolution of diatom markings, or the 

 discovery of final structural details, as that it has opened up new 

 avenues of research, and has even placed us in possession of all 

 that is now known under the term of Bacteriology, while the 



