228 RAMBLES OF A NATURALIST. 



may in some degree be regarded as the flower of a 

 singular production, known in botany by the name 

 of Mycelium. This production is composed of a 

 number of very fine filaments forming a kind of net- 

 work, on which is developed the fleshy substance, 

 vulgarly known as the mushroom. Now the My- 

 celium of an isolated Agaricus bears considerable 

 resemblance to other vegetable productions, and to 

 those kinds of mould or mucor which are formed upon 

 decayed wood in damp and dark places. Botanists, 

 however, seeing that they were propagated without 

 any change of form, divided them into special groups, 

 one of which is named Mucedina. Some years ago, 

 however, it was discovered by M. Dutrochet *, who 



* Dutrochet, a member of the Institute, was born in 1776, and 

 died at Paris in 1847. He did not devote himself to science until a 

 comparatively late period of his life, when happening by accident to 

 procure the -works of Spallanzani, he was so deeply impressed by 

 the value of the labours of this illustrious physiologist, that he 

 resolved, if possible, to follow in his steps, a resolution which he 

 immediately put anto practice by directing his attention to the 

 Rotifers, and to the singular faculties which we have already 

 described in them. He then successively investigated the different 

 membranes of the foetus, the development of birds, the formation 

 of bone, the regeneration of feathers, &c. In the midst of his 

 researches, he, for the first time, was led to consider phenomena, 

 which, although they had already been seen by others, had either 

 been neglected or forgotten. M. Diitrochet, fully comprehending 

 the importance of these phenomena, studied them with much 

 attention, and soon obtained general results, which led him to the 

 discovery of Endosmosis a discovery which he made known in 

 1826, and which will immortalise his name. 



Up to that period, the rising of the sap in the tree, as well as the 

 passage from one cavity into another, of the different liquids 

 contained in plants no less than in animals, had been attributed to 



