250 SUMMARY OF CURRENT RESEARCHES RELATING TO 



that the omission of methylen-blue gives better pictures. The films 

 are afterwards contrast stained for a minute or so in weak aqueous 

 solution of methylen-blue. 



For differential diagnosis it is advised to immerse the stained slide in 

 the decoloriser for not less than four and not longer than twelve hours. 

 If 25 p.c. sulphuric acid be used, the slides should be left in the acid 

 for at least sixteen and not more than twenty-four hours, and after 

 thoroughly washing with water they are contrast stained with aqueous 

 methylen-blue, dried and mounted. 



•C5) Mounting, including Slides, Preservative Fluids, etc. 



V ill agio — Modern Mounting Methods, continued. 



English Mechanic, Ixxix. (1904) pp. 13, 14, 83-4. 



x ' (6)1 Miscellaneous. 



Iodine-Calcium Nitrate, a new reagent for Cellulose.* — E. L. 

 Seeliger recommends the following for the recognition of woody ma- 

 terial in paper : Iodine • 1 ; potassium iodide 0*5; calcium nitrate 

 (Ca(N0 3 ) 2 +4H 2 0) 30 '0, and. water 50 -0. By this, cellulose in its 

 purity is stained light to dark blue, linen dark red, and Avoody material 

 and woody fibres (as jute) yellow brown. By this reagent, also, can be 

 distinguished the cellulose of conifers from that of other trees — the 

 former staining reddish, and the latter blue. The cellulose of conifers, 

 if bleached, takes on a violet tinge, and if unbleached, a yellowish one. 



The Agglutinoscope, an Apparatus for facilitating the Macro- 

 scopic observation of Agglutination in the Test-tube.f — H. Jaeger has 

 devised the following apparatus. Three boards of wood are taken, and 

 two of them are joined to the ends of the third by hinges. These two 

 meet in the form of a roof-edge, but one of them is made to overtop the 

 other by a hand's breadth, the latter resting on a ledge on the former. 

 This arrangement screens the daylight from the observer, as he works 

 desk-wise at the lower board. Extending transversely across this, is a 

 slit 3 mm. wide, and about the length of a test-tube. Underneath the 

 slit-opening is fixed an elliptical electric lamp, the long axis of which is 

 parallel with the slit, and through which it sends a very bright beam of 

 light. The test-tube containing the solution to be studied is held by a 

 clamp almost horizontally above the slit, being thereby brightly illumi- 

 ned, and the observer, by means of lens fixed to the board, can readily 

 see even the smallest clumps. 



Prevention of Pedetic or Brownian Movements.! — For the purpose 

 of photography, or for measurement and counting, it is very objection- 

 able to have minute particles in constant motion. For preventing this 

 movement, J. H. Gage uses a 10 p.c. solution of gelatin, filtered through 



* Zeitsch. angew. Mikrosk., ix. (190:0 pp. 249-50. 



t Ceutralbl. Bakt. V Abt. Orig., xxxv. (1904) pp. 521-3. 



X Trnns. Amer. Micr. So?., xxiv. (1903) p. 21. 



