ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 837 



Thin Sections of Timber."- — For showing the structure of timber 

 Mr. E. B. Hough employs frames made of cardboard hohling three 

 samples of wood, each being about 2 in. wide aud 5 in. long, and from 

 1/80 to 1/200 in. thick. These exhibit the wood in three relations; one 

 slice being transverse across the grain, another running radially from 

 the outside towards the heart, and a third is a tangential section. The 

 first and second show both the sapwood and the heart. They also reveal 

 the grain aud the structure of the wood in a most beautiful manner. 

 These various frames are arranged in book form for the purposes of 

 study and examination. They retain all the characteristics of wood and 

 are easily recognized, while the effect of the light shining through them 

 .is to show the jieculiarities of the grain even more empLatically than 

 would be the case if one were looking at a mass of the wood. 



(4) Staining- and Injecting- 



Iodized Hsematoxylin.f — Sig. F. Saufelice having noticed that tissues 

 which had been treated with tincture of iodine stained more uniformly, 

 devised a compound of logwood and iodine. This mixture possesses the 

 advantage of giving the same stain as Boehmer's hfematoxylin to tissues 

 previously treated with tincture of iodine, and of thoroughly penetrating 

 pieces to be stained in toto. 



Another advantage is that, owing to its antiseptic qualities, it keeps 

 better than most hfematoxylin solutions. It is prepared by dissolving 

 0*70 gr. hfematoxylin in 20 gr. absolute alcohol, and 0*20 gr. alum in 

 60 gr. distilled water. The first solution is poured drop by drop into the 

 second. The fluid is then exposed to the light for 3-4 days ; 10-15 drops 

 of tincture of iodine are added, the fluid is shaken up and allowed to 

 stand for some days. Tissues stain in this solution in 12-24 hours ; 

 they are then transferred to 90 per cent, spirit acidulated with acetic 

 acid, in which they are left for the same time. 



Staining the Flagella of Spirilla and Bacilli. J — Dr. Trenkmann's 

 method for staining flagella is as follows : — 



A small drop of fluid containing spirilla is placed on a cover-glass ; 

 to this is added a large drop of distilled water, aud the two intimately 

 mixed. When dry, the cover-glass is placed at once in a fluid which 

 consists of 1 per cent, tannin and 1/2 per cent, hydrochloric acid. In 

 this fluid the preparation remains 2-12 hours, and then having been 

 w-ashed is stained in dahlia (2 drops of a saturated alcoholic solution 

 to 20 water), fuchsin (2-4 drops of a saturated alcoholic solution to 

 20 water), gentian-violet (1 drop to 80 water), methyl-violet (1 drop to 

 80 water), methyleu-blue, iodine-green, methyl-green, vesuvin, Victoria- 

 blue. In the staining solution the preparation remains 2-4 hours, it is 

 then washed in water and examined. By all these anilin dyes cilia 

 are stained, most strongly by dahlia, fuchsin, or methyl-violet, but still 

 better by carbolic fuchsin (2 droj)s to 20 of a 1 per cent, carbolic acidj. 



Another method of staining is by means of catechu. Excess of 

 powdered catechu is macerated in water for some days and the extract 

 filtered. To 4 parts of this catechu solution are added 1 part of a 

 carbolic acid solution, and in this the cover-glass, prepared as before, is 



* Amer. Mon. Micr. Jourii., x. (1889) j). 187. 



t Journ. de Micrograpliie, xiii. (1889) pp. 335-7. 



X Ceutralbl. f. Bakteriol. u. Parasiteok., vi. (1889) pp. 433-6. 



