840 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



Fig. 114. 



Section-fixing.* — Dr. E. D. Bondurant suggests tlie following slight 

 variation of the method generally adoj)ted in the use of the elove-oil- 

 collodion process, which he has found to combine the convenience and 

 readiness of application of a liquid fixative with the undoubted advan- 

 tages oifered by the dry-film methods, in that it allows the preliminary 

 arrangement of the section or a number of sections on the slide, and the 

 easy removal of folds and wrinkles, which latter, especially with large 

 thin sections, is often impossible if tissue must lie as it falls, 



Place the section (paraffin imbedded) on a perfectly clean slide. 

 Arrange and smooth out folds with a camel's-hair brush dipped in 

 alcohol. Hold an instant over an alcoholic flame until the paraffin 

 partially melts and the section adheres. Paint over the section and 

 slide a thin film of the collodion mixture. Press down with the thumb 

 a bit of tissue-paper coated with same mixtui'e, in the manner recom- 

 mended by Dr. Keeves, to insure close contact. Planish with mounting 

 furceps, remove the paper, and place the slide on the brass table or water- 

 bath at the melting-point of paraffin, until the clove oil is evaporated, when 

 the section will be found firmly attached, and the slide can be passed 

 through benzol, alcohol, stains, &c., without danger of separation. 



Mayer's albumen process can also be used as above, and is satisfactory. 

 Frenzel's gutta-percha and Threlfall's 

 caoutchouc methods are also reliable, but 

 the author thinks the collodion process, 

 used in the manner described, is most 

 available and most certain in its results, 

 and he, for one, feels no need of a better 

 plan. 



Slide-rest for the Manipulation of 

 Serial Sections.f — The apparatus in- 

 vented by Dr. J. Dewitz for the manipu- 

 lation of several slides at a time, is made 

 of glass rod, and can therefore be easily 

 constructed by any person who possesses 

 a blow-pipe and some glass rod or tubing. 

 An inspection of it will show at once the 

 easiness of the manufacture. Glass rod of 

 two different thicknesses is required ; the 

 thicker is for the external part of the 

 frame, the thinner for the internal. The 

 illustration shows a frame suitable for 

 five slides, or ten if placed back to back, 

 but of course, as any number of turns 

 can be given to the parallel bars, an apparatus might be constructed for 

 an indefinite number of slides. The slides are slipped in from above, 

 and it will be seen that they can be kept in good position without danger 

 of interfering with one another. 



Mounting- " selected " Diatoms.^ — Mr. H. Morland " has two methods 

 of prejjaring slides of selected diatoms," one where the diatoms are gummed 

 down, the other where no cement is used. Choose only the finer and 



* The Microspope, ix. (1889) p. 191. 



+ Arch, f Mikr. Auat., xxxiii. (1889) pp. 416-8 (1 fit?.). 



X Jourii. Quekett Micr. Club, iii. (1SS9) pp. 318 30 (2 figs.). 



