ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 533 



clean one), we can only say, as in Miss Edgeworth's nursery story, 

 ' What ! no soap ? ' " 



A caution was subsequently given,* which well deserves the 

 attention of those who use soap. Many of the brands of soap contain 

 notable quantities of silica in various forms. Even the fine toilet 

 soaps contain it, the addition having been made for the purpose 

 of increasing their detersive power ; while to many of the more 

 common kinds kaolin, silica, &c., are added merely for the purpose of 

 increasing the weight. Therefore, in using soap, care must be taken 

 not to use such as will introduce insoluble matter and even diatoms 

 foreign to the original gathering. 



It will be remembered that we have already given f an abstract of 

 an article by Dr. H. Stolterfoth, describing his method of using soap 

 for cleaning diatoms. 



Mr. E. H, Griffiths endorses i the use of soap with, if necessary, 

 the subsequent use of nitric acid and carbonate of potash to bleach. 



Mr. F. Kitton has also tried it § on a subpeat deposit and a recent 

 fresh-water gathering from New Zealand, both of which, however, 

 required acid treatment before being sufficiently clear for mounting. 

 With Peruvian guano he found that the soap very much assisted in 

 getting rid of a quantity of colouring matter, and materially reduced 

 the amount of crude material. After pouring otf all that did not 

 subside in one hour he again boiled in soap and water, which further 

 reduced the quantity, but the residue was totally unfit for mounting 

 until further cleansed with nitric acid and chlorate of potash, and a 

 final wash with liquor ammonias. On the marine deposits such as 

 those from Virginia, California, Barbadoes, &c., soap seems to have 

 but little if any effect. 



To those who may be desirous of trying the soap process the 

 following hints may be useful : — 



1st. Carefully avoid hard water. 



2nd. Use the best yellow soap (the ordinary soap often contains 

 oil). 



3rd. If soap is used after the acid, remove all traces of the latter 

 with soft or distilled water. 



4th. Dissolve the soap in the water and pour it on the material so 

 as to make sure that no portion of it remains undissolved. 



The soap process does not, in Mr. Kitton's opinion, possess any 

 advantage over liquor ammonite in eliminating flocculent matter. 

 The preliminary boiling in soap and water, by getting rid of a portion 

 of the non-diatomaceous material, no doubt reduces the quantity of 

 acid required, but it will not supersede the use of it. 



Sullivant's Mechanical Fingers.jl — Mr. J. SuUivant, of Ohio, has 

 constructed mechanical fingers in two ways, which may be followed by 

 any one desiring such an appliance and having a stage forceps only, 

 or still better, a forceps and a nose-piece also. 



* Amer. Jouin. Micr., vi. (1881) p. 15. 



t See this Journal, iii. (1880) p. 1034. 



X Amer. Mon. Micr. Journ., ii. § Sci.-Gossip, 1881. pp. 102-3. 



il Amer. Mon. Micr. Journ., i. (1880) p. 186. 



