Chap. IX.] ESSENTIAL OILS, ETC. 173 



the open air for 42 hrs., but not a single tentacle expanded ; all the 

 glands appeared dead, except here and there one, which was still 

 secreting. It is evident that this oil is highly exciting and poison- 

 ous to Drosera, 



Oil of Cloves. A mixture was made in the same manner as in 

 the last case, and three leaves were immersed in it. After 30 m. 

 there was only a trace of inflection which never increased. After 

 1 hr. 30 m. the glands were pale, and after 6 hrs. white. No doubt 

 the leaves were much injured or killed. 



Turpentine. Small drops placed on the discs of some leaves 

 killed them, as did likewise drops of creosote. A plant was left for 

 15 m. under a 12-oz. vessel, with its inner surface wetted with, 

 twelve drops of turpentine; but no movement of the tentacles 

 ensued. After 24 hrs. the plant was dead. 



Glycerine. Half-minims were placed on the discs of three 

 leaves; in 2 hrs. some of the outer tentacles were irregularly in- 

 flected; and in 19 hrs. the leaves were flaccid and apparently dead; 

 the glands which had touched the glycerine were colourless. Mi- 

 nute drops (about sV of a minim) were applied to the glands of sev- 

 eral tentacles, and in a few minutes these moved and soon reached 

 the centre. Similar drops of a mixture of four dropped drops to 

 1 oz. of water were likewise applied to several glands; but only a 

 few of the tentacles moved, and these very slowly and slightly. 

 Half minims of this same mixture placed on the discs of some 

 leaves caused, to my surprise, no inflection in the course of 48 hrs. 

 Bits of meat were then given them, and next day they were well 

 inflected; notwithstanding that some of the discal glands had been 

 rendered almost colourless. Two leaves were immersed in the 

 same mixture, but only for 4 hrs. ; they were not inflected, and on 

 being afterwards left for 2 hrs. 30 m. in a solution (1 gr. to 1 oz.) 

 of carbonate of ammonia, their glands were blackened, their ten- 

 tacles inflected and the protoplasm within their cells aggregated. 

 It appears from these facts that a mixture of four drops of glycer- 

 ine to an ounce of water is not poisonous, and excites very, little 

 inflection; but that pure glycerine is poisonous, and if applied in 

 very minute quantities to the glands of the outer tentacles causes 

 their inflection. 



The Effects of Immersion in Water and in various Solutions on 

 the Subsequent Action of Phosphate and Carbonate of Ammotiia. 

 We have seen in the third and seventh chapters that immersion in 

 distilled water causes after a time some degree of aggregation of 

 the protoplasm, and a moderate amount of inflection, especially 

 in the case of plants which have been kept at a rather high tem- 

 perature. Water does not excite a copious secretion of mucus. 

 We have here to consider the effects of immersion in various fluids 

 on the subsequent action of salts of ammonia and other stimulants. 

 Four leaves which had been left for 24 hrs. in water were given 

 bits of meat, but did not clasp them. Ten leaves, after a similar 

 immersion, were left for 24 hrs. in a powerful solution (1 gr. to 20 

 oz.) of phosphate of ammonia, and only one showed even a trace 

 of inflection. Three of these leaves, on being left for an additional 



