44 r>iAT<)M.\< 



hoi' if inn of Diatoms. — We have already pointed out the 

 advantage, nay, even the necessity, of preserving the fruits of 

 all cleanings in dilate alcohol, in which they may rest in safety 

 awaiting the separation of the morphous from tlie amorphous. 

 And we may here add the advice to recommit the Diatoms to 

 alcohol finally before mounting, or incidentally, if interruption 

 temporarily arrest the perfect course of the isolation. The 

 methods of Mr. F. Okeden* by decantation, and by whirling in 

 an evaporating capsule or large watch-glass, as suggested by 

 Mr. J. A. Tulk,f we have found to answer every requirement if 

 they be as dexterously managed as they are ingeniously de- 

 vised. Bat we would call attention to a point, not hitherto 

 noticed, incidental to the decantation process, and which has 

 reference chiefly to the discoid forms. It is this: When the 

 Diatoms were nearly or quite free from foreign matters, and 

 beaker glasses were being used in the preparation, we observed 

 that entire disks adhered to the flat bottoms of the vessels. We 

 utilized this knowledge by emptying a beaker, by washing it 

 out quite freely with distilled water, and, finally, by detaching 

 and collecting the absolutely perfect Diatoms by means of a 

 soft camel's-hair pencil, well cleaned. In this way we have had 

 excellent success with many gatherings, but with none better 

 than the Nottingham earth, as was shown by some of our slides 

 exhibited in Chicago in March, 1871, at the reunion of the 

 State Microscopical Society of Illinois. 



We have now, by whatever process employed, attained the 

 cleaning and separation of the Diatoms, and have consigned 

 them to the temporary guardianship of dilute alcohol; but 

 there still remains for us the task of a final preparation of them 

 for mounting. By the plan adopted and suggested by Mr. 

 Okeden, they have been "sorted " as to size; yet one washing 

 more is necessary before we can transfer them to the expectant 

 slides. If the Diatoms were to be dipped out by a tube 

 directly, and dropped either upon a cover or a slide, the rapid 

 alcoholic evaporation would keep the whole field in agitation, 

 and the objects would eventually group together in drying, and 



*Metkod of Washing Diatomaceous Earths and Clays ; " Quarterly 

 Journal of Microscopical Science," Vol. Ill, p. 158. 



fOn the Cleaning and Preparing of Diatoms, Vol. XI, No. 3, III. 



