440 Miscellaneous, 



in all the leaves, both old and new, without exception : it is an actual 

 febrile movement, a violent shivering. It is especially perceptible 

 along the undulated margins of the leaves, and on the two raised 

 auricles, which are merely prolongations of the limb beyond the 

 petiole. The pulsations, still numbering from 100 to 120 per minute, 

 had force enough to communicate the movement to the pot which 

 contained the plant ; and, although it weighed from ten to twelve 

 kilogrammes, the hand and the strength of a man did not prevent it 

 from shaking. This rhythmic agitation was also communicated to 

 a fine leaf of Slrelitzia Nicolai and to a large leaf of Fhilodeiidrum 

 pei'tusmny which last passed the impulse to some fine flowering 

 groups of Begonia manicata. 



We have not yet been able to ascertain the circumstances which 

 seem to determine the movement, nor those which appear to oppose 

 it, although we have observed it every day for three months. 



In the first place, we may almost deny the action of temperature, 

 although its influence is considerable upon the development of the 

 Aroidese, since they disappear geographically from the cold regions 

 of the earth. We have not seen the movements of the Colocasia 

 increased by a temperature of 30° C. (=86° F.), nor have we seen 

 them slackened by a temperature of 7°. 



Is it the development of the new leaf, which is always very rapid, 

 that excites the agitation ? This seemed to us to be the effect of the 

 leaf produced in January. The movement, at all times not very 

 regular and without fixed periods, ceased when the leaf had nearly 

 attained its growth. But in the case of the leaf produced in February 

 the agitation did not commence until after the nearly complete deve- 

 lopment of the limb. Why should tliere be this difference ? 



Eminent botanists have paid attention to various physiological 

 phenomena presented by Colocasia esculenta. MM. Schmidt, 

 Duchartre, and C. Musset have published very important memoirs 

 upon this plant, and have all occupied themselves with the emission 

 of sap by its leaves. M. C. Musset especially has determined with 

 ])recision the various phases of this transpiration, and ascertained 

 that during prsefoliation the sap was projected to a distance of several 

 centimetres, through two orifices, in the form of stomata, situated at 

 the apex of the leaf. ^M. Musset was able to count eighty-five 

 drops projected in one minute — a number which may have some 

 relation to the 100-120 pulsations per minute of our plant of Colo- 

 casia. 



M. Musset had the kindness to send me his memoir; and I greatly 

 desired to eee, as he had done, the fine drops shooting forth from the 

 apex of the unexpanded leaf. I have never been able to observe 

 them ; moreover the stomata of the apex have never presented an 

 orifice. At no period could I observe a single drop suspended from 

 the leaf, or falling from the extremity of its limb ; there was no trace 

 of humidity or of transpiration. I had, in a cooler house, a tuft of 

 Calla cethioj)ica placed in a basin ; and each leaf every moment let 

 fall upon the water the result of its transpiration. 



In another stove, also situated at Clermout, I observed a Colocasia 



