APPENDIX. 469 



Chemiker, 12, Baiersche Strassej Leipzig, Germany), or, if 

 ordered through any agent, should be ordered to be sent in 

 the original packages, signed and dated by him. This is in 

 order to ensure the due freshness of the products ; many of 

 them will not keep well for very long. 



Glass and other apparatus can be obtained as well as chemicals from the 

 above-quoted houses. I would call attention to the varied usefulness of the 

 "Siebdosen " or sieve-dishes of ZIMMEKMANN and SUCHANNEK (vide Zeit. f. 

 wiss. Mik., vii, 2, 1890, p. 159). They consist of a covered glass capsule 

 into which is fitted a " sieve " made of a watch-glass pierced with holes and 

 supported on legs. . It is evident that the arrangement is very handy, not 

 only for staining, washing out, treatment with vapours, &c., but for any 

 operation in which it is desirable to have specimens supported in the upper 

 layers of a quantity of reagent. They are sent out in a very neat form by 

 Dr. Griibler. 



Want of space compels me to suppress the lists of suggested reagents 

 given in the last edition under the headings "The Laboratory table " and 

 " The Zoologist's Travelling Case." Either collection may still be obtained 

 from Dr. Griibler, the latter in appropriate bottles, fitted into a case 

 measuring 1 foot 4 inches X 5^ inches X 4^ inches, at the price of about 

 2 5s., or a case somewhat larger, yet not too heavy to be carried in the 

 hand, at about 3. 



864. Cleaning Slides and Covers. The readiest way known to me of 

 freeing slides from balsam, damar, and cement is to wet with water and 

 scrape with an old knife, using afterwards, if necessary, one of the solvents 

 mentioned below. 



HANAMAN, Journ. Roy. Mic. Soc., i, 1878, p. 295 ; American Naturalist, 

 xii, p. 573. To a cold saturated solution of bichromate of potash add ^ of 

 its bulk of strong sulphuric acid (care must be taken on account of the heat 

 and vapours evolved). 



HENEAGE GIBBES, ibid., iii, 1880, p. 392. Place the cover-glasses in 

 strong sulphuric acid for an hour or two, wash well until the drainings give 

 no acid reaction ; wash first with methylated spirit, and then with absolute 

 alcohol, and wipe carefully with an old silk handkerchief. 



SEILEE, ibid., p. 508. New slides and covers are placed for a few hours 

 in the following solution : 



Bichromate of potash ...... 2 ounces. 



Sulphuric acid 3 fluid ounces. 



Water 25 



Wash with water. The slides may be simply drained dry ; the covers 

 may be wiped dry with a linen rag. 



Slides and covers that have been used for mounting either with balsam or 

 a watery medium are treated as follows : The covers are pushed into a 

 mixture of equal parts of alcohol and hydrochloric acid, and after a few days 

 are put into the bichromate solution and treated like new ones. The slides 



