Grafting of Bones. — Fecundation of Vegetables. 309 



may be engrafted on the bone of a living animal of the fame 

 or of a diHerent fpecies. 



In conjunilion with Vafalli, he has made experiments to 

 afcertain whether the opinion of the ancients, who pretended 

 that contagious difeafes are produced by infers, be true j but 

 their refearches have fliown them that this opinion has no 

 foundation, 



Pinel has publifhed numerous obfervations, which he has 

 had occafion to make, on idiots and maniacs. He fhows 

 that kind and gentle treatment, but attended with firmnefs, 

 often calms the fury of thofe unfortunate perfons, and is fre- 

 quently fufficient to reftore them to reafon. 



PHYSIOLOGY OF VEGETABLES. 



Desfontaines has given a memoir on the cultivation and 

 ufes of the date-tree, fo valuable to the inhabitants of hot 

 countries. Thefe palms, as is well known, are of the family 

 of the dioecia, the male flowers of which are borne on one 

 Ilalk and the female flowers on another. The male flowers, 

 deftined for fecundation, are detached from the trees about 

 the end of March, before the antherae have flied their farina. 

 They are prepared in fuch a manner that they can be tied to 

 the females : they are hung up and dried in the fliade ; and 

 in this manner thev will retain their virtue till the year fol- 

 lowing. Towards the end of April they are attached to the 

 female date-trees, which are thus fecundated ; becaufe it 

 would be very imprudent for men, whofe whole nourifhment 

 is confined to the fruit of this palm, and who inhabit the 

 bofom of the deferts, to truft for the fertility of thefe trees to 

 the winds, which, in fome cafes, may convey the fecundating 

 farina. 



Linnaeus made known a part of the wonderful phenomena 

 exhibited by the valifneria at the time of its fecundation. 

 Picot la Pcyroufe.has added fome new details. This plant 

 belongs to the dioecia. The male and female always grow 

 at the bottom of the water. At the moment when the male 

 is about to flower, its (talks, which are terminated by a flat 

 (heath, burft, and the flowers are thrown out on the furface 

 of the water ; where they unite, and float about at the plea- 



furc 



