CONTRACTILE FILAMENTS OP AGARICUS MUSCARIA. 81 



percent, is therefore strong enough to cause contraction though 

 not very rapidly. 



The effects of salt solutions are very different to the above 

 results. At 11.3 a.m. irrigated a preparation with 10 per cent, 

 solution of chloride of sodium, and contraction took place. As 

 far as I could see, the protoplasm lining the gland-cells began 

 to shrink and the filament to contract simultaneously. The pre- 

 paration was then washed with distilled water, and the gland- 

 cells rapidly recovered their form. I could not watch the 

 filament any more, as a floating object was washed on to the top 

 of the gland. Observation Vi'as transferred to a neighbouring 

 gland, on which a crumpled, half- contracted filament was seated. 

 At 11.17 I found that normal filaments were protruding along- 

 side of the crumpled filament. At 11.42 the crumpled filament 

 had almost recovered, and normal filaments were found on a 

 neighbouring gland. 



In some other experiments made with salt solution the gland 

 recovered its normal appearance on being washed with distilled 

 water, and fresh vigorous filaments were protruded ; yet the 

 actual filaments which had been made to contract retained their 

 spherical figure as long as I watched the preparation. These 

 results agree with De Vries'^ observations, who points out (p. 8) 

 that vegetable cells, after being treated with very strong solu- 

 tions of harmless salts, recover perfectly if washed in water. 



As before noticed, irrigation with 10 per cent, solution of 

 chloride of sodium produced shrinking of the wall-proto- 

 plasm and contraction of the filament nearly simultaneously. 

 The same fact was observed with 5 per cent, solution. Here the 

 filament contracted first, and then almost immediately the pro- 

 toplasmic lining of the stalk-cell of the gland. The similarity 

 in behaviour between the filaments and the cell-protoplasm 

 was shown again by irrigating with 3"5 per cent. NaCl, which 

 neither produced cell- or filament-contraction. Again, a pre- 

 paration was treated with 4 per cent. NaCl; the filament contracted 

 slowly, and then the stalk-cell and the whole gland. 



Nevertheless, the behaviours of the filaments and of the cell- 

 protoplasm are not always precisely similar ; for on two occasions 

 irrigation with 1 per cent, chloride of potassium and chloride of 

 sodium produced contraction of filaments, while it caused no 

 shrinking of the cell- wall protoplasm. And the converse case 

 has already been noticed, in which 30 per cent, solution of sugar 

 produced shrinking of the gland-cells, but not contraction of the 

 filaments. The remarkable difference between the strengths of 



' ' Bot. Zeitung,' 1877, No. 1, and ' Untersuchungen iiber die Mechau- 

 ischeu Ursachen der Zellstreckung,' Leipzig, 1877. 



VOL. XVIII.-««-NEVV^ SER. F 



