M. Lestiboudois on the laticiferous Vessels of Plants. 267 



XXVI. — Second Communication on the Vasa Propria, Laticiferous 

 Vessels, ^c, of Plants, By M. T. Lestiboudois*. 



This second communication by M. Lestiboudois was made to the 

 Academy of Sciences in April last, and forms a continuation of 

 the memoir previously presented to that learned body, of which a 

 translation appeared in the 'Annals' for June last (vol.xi. p. 402). 



We have established (writes M. Lestiboudois) beyond doubt 

 the existence, in certain plants, of vessels containing coloured 

 liquids. 



It has indeed been held that such vessels are primitively no- 

 thing more than passages or interspaces, permeated by a thread 

 of granuliferous fluid, and that the formation of a wall to limit 

 them as vessels is a subsequent event. But what does this 

 signify ? Are there not cells whose walls are only developed 

 subsequently to the nucleus ? and such cells are as perfectly 

 characterized as others. If therefore these vasa propria have 

 such delicate walls as can only be detected at a later period of 

 their existence, they nevertheless constitute a vascular system 

 distinguished by the characters heretofore described. In this 

 we have an established scientific fact. 



However, it must be conceded that this vascular system is 

 not in all points a counterpart of that of the blood-vessels of 

 animals. In the leaves these proper vessels form at their origin, 

 by means of their ramifications, a capillary network ; but at their 

 termination they do not further divide into delicate branches, 

 to distribute, like the blood-vessels of animals, the nutritive 

 juices to the several organs; they do not extend themselves into 

 all parts ; they leave spaces, often of considerable extent, between 

 them, and the liquids they enclose can only reach the surround- 

 ing tissues by percolation through their walls ; and consequently 

 they are not better adapted for the distribution of nutritive ma- 

 terial than fibres and cells, and indeed not so well fitted for that 

 purpose as are passages and lacunse. There is therefore a notable 

 diff'erence between them and the sanguiferous system of animals, 

 the distributor of nutritive material, and one such as may be 

 held to intimate that they do not fulfil precisely the same 

 purpose. 



We have now to inquire whether the fluid contents of the 

 vasa propria are engaged in an act of circulation. On placing 

 under the microscope a petal which has been rendered transpa- 

 rent by soaking in oil, the globules are perceived in rapid mo- 

 tion. This movement may be very completely seen in the living 

 parenchyma of the stipule of Ficus elastica, after the removal of 

 the epidermis from both surfaces. In this preparation the micro- 



* Translated by Dr. Arlidge from the ' Comptes Rendus ' for April 27, 1 863. 



18* 



