ZOOLOGY AND BOTANY. MICROSCOPY, ETC. 687 



therefore represents a movement of the section through 0*002 mm. There is 

 also an automatic arrangement. For wet cutting a fixed tray is added. A 

 second form of the instrument has a movable tray, which can be lowered for 

 dry or raised for wet cutting. In the latter case the object-holder is immersed. 

 It is claimed that this plan of cdnstruction obviates the inconveniences of those 

 microtomes which are reversible for immersion.] 



Le Naturaliste, VIII. (1S86) pp. 241-.S (8 figs.). 

 Journ. de Microgr., 1886, pp. 507-12 (6 figs.). 

 Haensell, p. — Le Microtome et ses applications a I'anatomie de Toeil. (The 

 microtome and its applications to the anatomy of the eye.) 



Bull. Clin. Nat. Oplthalm., IV. p. 106. 

 E ED DING, T. B.— Uses of Celloidin. The Microscope, VII. (1887) pp. 43-5. 



Rosenberg, P. — Eine neues Microtom. (A new microtome.) 



Anat. Anzeig., 1886, pp. 211-3. 

 T Y A s, W. H. — Golding-Bird's small Ice Freezing Microtome. 



Trans, and Ann. Rep. Manchester Micr. Soc, 1886, p. 70. 



(4) Staining- and Injecting'. 



Fixing and Staining Nuclei.*— Mr. D. H. Campbell writes, that the 

 following methods have been found to give excellent results in the study of 

 nuclei. The observations were chiefly made with the mother-cells of the 

 spermatozoids of various ferns, but the nuclei of vegetative cells also gave 

 very inptructive preparations. 



In order to fix the nuclei, the prothallia were placed in aqueous solu- 

 tions of chromic or picric acid or corrosive sublimate. The chromic acid 

 solution should be a 1 per cent, solution; the others concentrated. In 

 these solutions they should remain from one to two hours, though in the 

 corrosive sublimate solution less time is required. The chromic and picric 

 acid preparations must be washed in several waters before staining. It 

 has been found a good plan to leave them overnight in abundant fresh 

 water before the final washing. The sublimate preparations may be trans- 

 ferred to absolute alcohol, in which they should remain several hours. 



The specimens are now ready for staining. The best results were 

 obtained with hfematoxylin and gold chloride. The secret of good 

 hfematoxylin staining is to use a very dilute solution ; three or four 

 drops of the prepared solution in a watchglassful of distilled water, and 

 to allow the specimens to remain in this for at least twenty-four hours. 



After taking the specimens from the haematoxylin solution, they must 

 be passed successively through 50 per cent., 70 per cent., and absolute 

 alcohol before mounting. Half an hour is usually sufficient for each of the 

 alcohols. For immediate examination they may be mounted in glycerin, 

 but for permanent preparations first in origanum oil, and then transferred 

 to Canada balsam (dissolved in chloroform.) 



The gold chloride method is simpler, and is found to answer admirably 

 for specimens fixed in picric or chromic acid ; but with those fixed with 

 the corrosive sublimate or alcohol, it has not answered so well. A few 

 drops of 1 per cent, gold chloride in water are placed in a watchglass 

 almost half-filled with distilled water, and the specimens are allowed to 

 remain from one-half to one hour, the solution being kept in the dark. 

 Strasburger recommends a trace of HCl, but with the picric and chromic 

 acid preparations, although thoroughly washed, the author found this un- 

 necessary. The specimens are then thoroughly washed, being at the 

 same time exposed to the light and finally mounted in glycerin. With 

 alcohol material, haematoxylin was found to give the best results. 



The above notes embody (the author says) nothing specially new, but 

 may be useful as a memorandum of work actually done. 



* Bot. Gazette, xii, (1887) p. 40, 



