336 Meyen's Report for 1839 on Physiological Botany. 



that this subject was talked over at the meeting at Freiburg, 

 and that several botanists, as M. Treviranus, Von Martius, &c. 

 declared that they had seen this motion of the latex only in 

 injured plants. M. de St. Hilaire, who was present, was asked 

 ■whether the members of the French Academy had convinced 

 themselves of the correctness of M. Schultz's statements, and 

 he replied, that " For the present they had only translated the 

 paper, but had as yet formed no judgement thereupon." 



Rather contradictory to the above are several of the state- 

 ments made by M. Schultz in a late paper on the results of 

 his work, in which, among others, he very modestly says, 

 " We Avill satisfy ourselves with having made the beginning, 

 and with having pointed out the principles of a determinate 

 direction of the science, the further development of which the 

 judgement of the French Academy will promote not less than 

 the publication of the memoir." 



There are two things which it appears to me, from my own 

 observations, M. Schidtz has represented very incorrectly, viz. 

 the three hypothetical stages of development of the vessels of 

 the latex, the contracted (vasa laticis contracta), the expanded 

 (vasa laticis expansa), and the articulated (vasa laticis ai'ticu- 

 lata) ; and moreover the bringing together of the most differ- 

 ent formations under the common name of the latex-vessels, 

 or " vessels of the vital sap." 



The contracted latex-vessels are said to form the youngest 

 state of the vessels, and in them there is the greatest vital ac- 

 tivity ; they possess (it is said) the power of expanding and 

 contracting themselves, and indeed to such ^n extent, that 

 they almost disappear [!] . In the expanded latex-vessels the 

 expansion predominates, but they still possess a contractile 

 power. At a later period, by means of the interrupted con- 

 tracted parts of the latex- vessels, they become articulated, and 

 the contracted and expanded parts have now become perma- 

 nent. 



From my own observations, I must declare the whole de- 

 scription of the different stages of development of the latex- 

 vessels to be entirely false : the latex-vessels can neither con- 

 tract nor expand ; and that the articulation is not caused by 

 contraction, may be seen by a simple observation of such cells 

 as lie one above the other and are filled with latex. Indeed 

 the whole description is so strange, that I did not know for se- 

 veral years what M. Schultz meant by his contracted latex- 

 vessels, until he published the remarkable treatise mentioned 

 in the former Report, p. 74. Herein it was seen that M. Schultz 

 had denominated "conti'acted latex- vessels" those fine cur- 

 rents of gum which are so often seen in the cells of plants, 

 both in the Fungi and the Phanerogams, and which are to be 



