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530 



MR. S. LE M. MOORE'S STUDIES 





























Keagent. 



Time during 



which experiment 



lasted. 



Iron acetate ... 



Ferrous sul- 

 phate 



12.55 p.m. to 4 p.m. 



2.45 p.m. to 4 p.m. 



Potassium ]i 11QAl , A 

 bichromate. > ' H .30 a.m. to 4 p.m. 



Ammonium 

 molybdate 



11.15 a.m. to 4 p.m 



Copper acetate. 



1.20 p.m. to 4 p.m 



Copper sul- 

 phate 



3 p.m. to 4 p.m. 



Effect produced. 



Tannin not yet completely 

 shown up. 



Effect imperfect. 



Many idioblasts well stained, 

 but many not yet stained or 

 but slightly. 



( Many cells beautifully coloured : 

 | many not coloured at all. 

 ^ Addition of ammonium chlo- 

 | ride to the molybdate caused 

 ^ no perceptible difference. 



A pale yellow-pink or pale 

 brown colour in most of the 

 tannin- cells. 



Grey precipitate in a few of the 

 tannin-cells. 



















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On examining, next morning, strips of epiderm placed over- 

 night in the above solutions, the effect characteristic of each was 

 well seen. 



In the subsidiary cells of Grevillea robust a the tannin shows 



up immediately with Nessler's fluid, as also with osmic 



acid. 



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Some of the ordinary reagents, such as iron acetate, will act 

 directly upon a few of the cells ; but many cells remain uncoloured, 

 and several hours must elapse before they stain. It is further 

 to be noted that in every case in which an immediate brown pre- 

 cipitate is given with Nessler's fluid, a blue-black precipitate is 

 thrown down with iron salts. 



Group II.— We have seen that tannin in Rosa canina gives a 

 brown precipitate with Nessler's fluid ; but the hairs upon the 

 young leaves take at first a yellow colour, and in some of them 

 this passes into a brown. It would hence appear that we have 

 two kinds of tannin in these hairs. Nor is this matter for 



wonder, since Dufour * finds both iron-blueing and iron-greening 







Bull. Soc. Vaud. 1886. Abstracted in Journ. B. Micros. Soc. 



1887, 





p. 257. 

























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