M. Dutrochet's Discoveries in Vegetable Physiology. 103 



Art. XVII. — Account of the Discoveries in Vegetable Physio- 

 logy, particularly those respecting the motion of the Sap, 

 made by M. Dutrochet, Corresponding Member of the 

 Academy of Sciences. 



The important discoveries of M. Dutrochet may be justly con- 

 sidered as forming an era in the history of vegetable physio- 

 logy. They have been published in two different works, one 

 of which appeared at Paris in 1826, under the title of V Agent 

 immediat du Mouvement vital devoile dans sa Nature et dans 

 son Mode oV Action chez les Vegetaux et chez les Animaux, 

 while the other appeared in the Annates de Chimie, fyc. for 

 August 1827, entitled Nouvelles Observations sur VEndos- 

 mose et VExosmose, et sur le Cause de ce double Phenomene. 



Of the discoveries contained in the first of these works we 

 shall lay before our readers only a general account, particu- 

 larly as an able review of it has already appeared in an Eng- 

 lish work ; but of the second we shall give an entire transla- 

 tion. 



M. Dutrochet has demonstrated that the sap of plants is 

 transmitted through what he calls tubes corpusculiferes, the 

 lymphatic vessels of De Candolle, and the fausses trachea? of 

 Mirbel. These vessels are situated in the wood, whether it is 

 in the condition of alburnum or of old or hard wood (the du- 

 ramen of our author.) These tubes do not exist in the bark, 

 nor in the pith or medulla. They possess no valves, and have 

 no lateual communication with each other. » 



That the cause of the motion of the sap resides in the roots, 

 may be proved by making successive sections of the stem of a 

 vine in spring. When it is cut near the earth, the part cut off 

 ceases to bleed when the section is made, while the surface at- 

 tached to the root bleeds freely ; and this continues to be the 

 case till we come to the radicles, at the extremities of which 

 are the spongioles and fibrils, small conical bodies, in which 

 the power which impels the sap resides. These spongioles 

 communicate directly with the lymphatic tubes which pass up 

 the stem. They consist of cellular tissue, the central parts of 

 which are oblong cells, the elements of the lymphatic tubes 



