ALKALOIDS 81 



causes the appearance of numerous solid granules and a rapid loss of 

 plasticity. It is possible that this may be connected with the decompo- 

 sition of basic compounds of Potassium, Calcium, Magnesium, or Iron with 

 proteids, and the production of the corresponding salts of these metals, 

 whereas the vacuolation produced by alkalies may be due to their liberat- 

 ing soluble carbo-hydrates or organic acids held in loose combination by 

 proteid molecules. 



SECTION 35. Alkaloids. 



Dutrochet (I.e., p. 71) found that dilute watery solutions of opium 

 caused a temporary stoppage of streaming in Chara within six minutes, 

 which lasted for fifteen minutes, and was then followed by a resumption of 

 slow streaming, ceasing after half an hour. With more dilute solutions the 

 primary retardation or stoppage was followed by more active streaming 

 than normal. 



Caffein and Antipyrin. By using 01 per cent, to 0-5 per cent, 

 solutions of Caffein, it is easy to cause a progressive retardation of 

 streaming, and an increasing vacuolation of the protoplasm. The latter 

 is especially well shown by the root-hairs of Trianea l . Recovery is often 

 possible after the complete cessation of streaming in Trianea, Elodea, 

 Vallisneria, &c., and more rarely in Chara and Nitella, if the stoppage is 

 not unduly prolonged. In such cases, streaming gradually becomes active 

 again in one to six or eight hours as the protoplasm assumes its normal 

 appearance. 



The action of antipyrin is similar in character but weaker 2 . Thus 

 four hours' immersal in solutions of from I to 2 per cent, strength 3 causes 

 streaming to cease in Elodea and Vallisneria, and to become very slow 

 in Chara and Nitella, recovery being possible in all cases. After six to 

 eight hours, streaming ceases in the last two plants, but recommences 

 in water in from five to fifteen minutes, and becomes moderately active 

 in one to two hours. After longer exposures than this, many cells are 

 fatally affected in Chara, Nitella, and Vallisneria, and a few in Elodea also. 



Although both caffein and antipyrin exercise a pronounced effect 

 upon the nervous systems of the Vertebrata, they are by no means such 

 virulent poisons as are Muscarin, Atropin, Eserin, Veratrin, and Curare, 

 and it is of considerable interest to compare the actions of these poisons 

 upon the nerves and contractile organs of animals, and upon the stream- 

 ing protoplasm of plants. For example, Veratrin causes a nerve-muscle 



1 Cf. Klemm, 1. c., pp. 39-40. 2 Cp. Hauptfleisch, 1. c., p. 221. 



3 The plants were passed through solutions of o-i per cent., 0-2 per cent., 0.5 per cent., and 

 i per cent, or 2 per cent, strength at intervals of a few minutes. This avoids any plasmolytic shock- 

 effect. 



