Mamires. 81 



on their edges with a row of strong prickles. Flies, attracted 

 by honey which is secreted in glands on their surface, venture 

 to alight upon them ; no sooner do their legs touch these 

 parts, than the sides of the leaves spring up, and locking 

 their rows of prickles together, squeeze the insects to death. 

 The well-known Sensitive Plant (Mimosa sensitiva) shrinks 

 from the slightest touch. O'xalis sensitiva and Smith/a sen- 

 sitiva are similarly irritable, as are the filaments of the stamens 

 of the berberry. One of this sensitive tribe, i^edysarum 

 gyrans, has a spontaneous motion ; its leaves are frequently 

 moving in various directions, without order or cooperation. 

 When an insect inserts its proboscis between the converging 

 anthers of a kind of Dog's-bane ( Apocynum androssemifoiium), 

 they close with a power usually sufficient to detain the intruder 

 until his death." The more I study the phenomena of veget- 

 ation, the more I feel convinced on this point. How often 

 have I heard a farmer reply to an observation upon the tardy 

 growth of turnips, — " They will not grow apace, until their 

 leaves are large enough for the wind to take hold of them ;" 

 and this is only because plants cannot be healthy and vigor- 

 ous without exercise. Mr. Knight found that trees which 

 were regularly shaken every day in his green-house, grew 

 more rapidly and strong than others which were kept still. 



The stimulating powers of excrementitious manures arise 

 from the salts of ammonia they contain. Sir H. Dcivy found 

 vegetation assisted by solutions of muriate of ammonia (Sal 

 ammoniac), carbonate of ammonia (Volatile salt), and acetate 

 of ammonia. Night-soil, one of the most beneficial of ma- 

 nures, surpasses all others in the abundance of its ammoniacal 

 constituents in the proportion of 3 to 1 . . It may be observed 

 that the nearer any animal approaches to man in the nature 

 of its food, the more fertilising is the manure it affords. I have 

 no doubt that a languishing plant, one, for example, that has 

 been kept very long with its roots out of the earth, as the 

 orange trees imported from Italy, &c., might be most rapidly 

 recovered, if its stem and branches were steeped in a tepid, 

 weak solution of carbonate of ammonia ; and, when planted, an 

 uncorked phial of the solution were suspended to one of the 

 branches, to impregnate the atmosphere slightly v/ith its stimu- 

 lating fumes. 



{To he continued^ 



Vol. IV. — No. 14. 



