264 SUMMARY OF CURRENT RESEARCHES RELATING TO 



an aqueous solution of Bordeaux red. This procedure was the best, 

 except for fertilisation stages. 



In order to differentiate the sperm within the egg from the deuto- 

 plasm, the eggs were stained with Delafield's hematoxylin, and differen- 

 tiated with a weak solution of picric acid in 90 p.c. alcohol. This 

 makes the deutoplasm reddish yellow, but leaves the sperm black. 



Later experience found that Brazilin was superior to iron-hasmato- 

 xylin. After sectioning, the eggs were mordanted in a solution of 

 iron in 70 p.c. alcohol for 30 to 60 minutes, and then stained for 30 

 minutes to 2 hours in a J p.c. solution of Brazilin in 70 p.c. alcohol. 

 The Brazilin gives a double stain, nucleoplasm staining intensely black, 

 and cytoplasm a Bordeaux red hue. It has the further advantage of 

 being a shorter process, and that it rarely overstains. 



Demonstrating Enzyme-secreting Cells.* — H. S. Reed, for his 



stud}- of the enzyme-secreting cells in the seedlings of Zea Mays and 

 Pharnix dactylifera, used the following killing fluids : — (1) Saturated 

 solution of picric acid in 50 p.c. alcohol ; (2) Aqueous picro-corrosive 

 fluid. This was made by adding 1 vol. of saturated aqueous solution 

 of mercuric bichloride to 3 vols, of saturated aqueous solution of picric 

 acid. After lying 12-18 hours in this fluid, the material was washed 

 in water and dehydrated in alcohol ; (3) Kleinenberg's picro-sulphuric 

 acid ; (4) Chrom-osmo-acetic acid ; | (5) Iridium chloride in acetic 

 acid (1 p.c. aqueous solution of iridium chloride, 25 c.cm. ; glacial acetic 

 acid, 75 c.cm.) ; (6) Worcester's killing fluid (saturated aqueous solution 

 mercury bi-chloride, 96 parts ; formalin, 4 parts ; 10 p.c. acetic acid, 

 10 parts ; formic acid, 5 drops to each litre of solution). The tissue was 

 immersed for 10-20 hours, then transferred to 70 p.c. alcohol which 

 contains 1 p.c. potassium iodide ; (7) Saturated aqueous solution of 

 mercury bi-chloride in absolute alcohol. The paraffin sections were 

 stained with picro-nigrosin ; Kleinenberg's hasrnatoxylin ; Heidenhain's 

 iron-alum hasmatoxylin ; Zimmermann's-fuchsin-iodine green ; Gram's 

 method ; eosin-toluidin-blue ; eosin and anilin-blue ; eosin and gentian 

 violet ; Flemming's triple stain. 



The best staining results were obtained from the eosin-toluidin-blue. 



Chamberlain, C. J. — Celloidin method for hard tissues. 



[A note in reference to E. C. Jeffrey's method given 



above.] Bot. Gazette, xxxviii. (1904) p. 145. 



„ „ Ditto. Tom. cit., pp. 382-3. 



Jeffrey, E. C. — Ditto. Tom. cit., pp. 381-2. 



(4) Staining: and Injecting. 



Staining Protozoa 4 — F. Marino found that azur in aqueous or 

 alcoholic solution stains well the nucleus and protoplasm of Protozoa 

 fixed in alcohol, and that very dilute aqueous solution of eosin (1 : 20,000) 

 differentiates them. 



A mixture of an aqueous solution of methylen-blue and of azur 



* Ann. Bot., xviii. (1904) pp. 269-87 (1 pi.). 



t Mottier's formula, Pring. Jahrb., xxx. p. 170. 



j Ann. Inst. Pasteur, xviii. (1904) pp. 761-5 (1 pi.). 



