844 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the centre, and with the aid of a lens arrange as straight a line as possible, 

 seeing at the same time any air-bubbles are dislodged either with a needle- 

 point or gentle pressure of some kind. Apply the jelly, dip your cover in 

 warm water, put over all, and gently press down. In adopting this method, 

 you are not very sure of keeping the moss as artistically displayed as you 

 could wish, but the judicious use of a needle, quickly handled before the 

 jelly sets, will put right any serious defect. Eiag and finish as with other 

 slides. This is Captain P. G. Cunliffe's method, and was used by him in 

 preparing his slides for the Manchester Cryptogamic Society, and which 

 were acknowledged by all to be beautifully mounted specimens." 



Cleaning and arranging Diatoms.* — Dr. F. S, Newcomer proceeds as 

 follows : — He uses a test-tube 10 in. long and 1/4 in. in diameter, cuts the 

 Zoslera marina into inch lengths for convenience of boiling, boils to wash 

 out the chloride of sodium, then boils in bicarbonate of soda to break up 

 the fibres of the plant, then washes out the soda, and having poured into a 

 Berlin dish, evaporates the remaining water. Sulphuric acid is then 

 added until the organic matter is completely charred. The mass is then 

 deflagrated with chlorate or nitrate of potash. After the acid is cooled, 

 about a quart of distilled water is poured in gradually, and stirred the 

 while. The acid having been removed, any flocculent material is got rid of 

 by boiling with soap (not more than 10 grs. to the test-tube). When the 

 soap is washed away, the diatoms will be clean and bright. The diatoms 

 are extracted by pouring the material into a Berlin dish ; the diatoms will 

 be found at the top and the sand, if any, at the bottom of the dish. It is 

 not advisable to throw away the sand, as the largest diatoms are frequently 

 found among it. The material is preserved in a mixture of equal parts of 

 spirit and water. 



Diatomaceous earths require great patience ; the Barbados material, in 

 which there are traces of iron, is best treated at first with a concentrated 

 solution of citric acid. 



In arranging geometric forms of diatoms a guide slide with micrometer 

 circles is used. On this is placed the cover-glass by moistening the surface 

 of the guide slide by breathing upon it ; then centered with a pocket lens. 

 The best fixative for the purpose is that of Mr. Febiger : glacial acetic acid 

 1'2 fluid drachms, gelatin 2 drachms, alcohol 1 fluid drachm. The gelatin 

 is dissolved by adding the acid over a water-bath, and after the alcohol is 

 mixed in the whole is filtered. The fixative is then spread across the face 

 of the cover-glass by means of the finest cambric needle. The slide on 

 which the diatoms are to be arranged is then fixed on a turntable, and a 

 ring the size of the cover-glass run on with any anilin ink or colour ; the 

 slide is then turned over, heated, and a drop of balsam placed upon it and 

 the cover-glass on it, the anilin ring on the under side being used as a guide. 

 The slide is finished off by running the flame of a spirit-lamp round the 

 edge of the cover-glass. The flame of the lamp must be turned down until 

 it is blue. 



Cleaning Diatomaceous Mud.j — Dr. G. H. Taylor does not agree with 

 Mr, C. H. Kain as to the avoidance of muds in the collection of diatoms. 

 If muds are avoided, some of the finest specimens obtainable are missed. 

 The author is now engaged in working up the muds of the North Carolina 

 coast. This mud is most difficult to clean, that is, to eliminate the sand ; 

 as much as 250 gallons of water have been used before obtaining enough 

 material in a cleaned state to cover the bottom of a half-drachm phial. 



* Proc. Amer. Soc. Micr. 9th Ann. Meeting, 1886, pp. 128-30. 

 t Bull. Toirey Bot. Club, xiv. (1887) pp. 141-3. 



