220 Messrs. Gladstone on the Growth of Plants in various Gases. 



decreased very much in volnme, but was beginning to increase 

 again towards the close, when the plant was becoming unhealthy 

 in appearance. 



A precisely similar experiment was made with light carburetted 

 hydrogen prepared from the acetates in the place of the carbonic 

 oxide : the growth of the plant was similarly affected, but it 

 proved that this gas (at least in the proportion of seven parts of 

 carburetted hydrogen to ten of air) is not poisonous to the bulbous- 

 rooted plant in question. We have not performed any experi- 

 ments with unmixed carburetted hydrogen or olefiant gas ; it is 

 to be expected, however, that they would be found equally inno- 

 cuous with carbonic oxide, hydrogen, and others which have been 

 examined. Drs. Turner and Christison found no deleterious 

 effect in twenty-four hours from a mixture of 4^^ inches of olefiant 

 gas, with 100 times as much air. The action of gaseous hydro- 

 carbons upon plants is a separate branch of inquiry, as it involves 

 the interesting question as to whether these gases are capable of 

 being assimilated or decomposed by the living organism of the 

 vegetable, and thus of contributing to its support. 



There is a peculiar circumstance attending the growth of the 

 plants in most of the experiments above detailed, as also in the 

 comparative ones made with atmospheric air, — a circumstance 

 which may be constantly observed in '' Ward's Cases,'' though 

 perhaps not in so striking a manner. It is this : — they increase 

 at first somewhat in height, and the leaves or flowers may open 

 a little further than when first placed in the confined atmosphere, 

 but after a day or two their growth appears retarded without any 

 signs of decay. Thus in the experiment with the crocus in mixed 

 light carburetted hydrogen and air, the bulb was placed in the 

 inverted vessel on Dec. 27th ; rootlets and leaves of about 5 inches 

 in length speedily shot forth, but then the functions of the vege- 

 table seemed suspended, and it remained in the month of July 

 just as it was in February, a crocus with delicate green leaves 

 opening for the protrusion of the flower-stalk. 



These results indicate that gases may be divided into two great 

 classes in respect to their action upon vegetable life ; namely, 

 those which are decidedly poisonous, and those which exert no 

 deleterious influence. The poisonous gases have been investi- 

 gated by Drs. Christison and Turner in the memoir already ad- 

 verted to more than once ; they are sulphurous acid, sulphuretted 

 hydrogen, hydrochloric acid, chlorhie, and cyanogen ; and a very 

 minute quantity of any of these is found to destroy plants im- 

 mersed in them for only a few hours ; indeed some of them, 

 sulphurous acid for instance, are decidedly more injurious to 

 vegetable than to animal life. In respect to hydrogen, Davy 

 came to the conclusion that it was injurious to some plants, but 



