H2 HISTORY OF BOTANY 



Schleiden's textbook forms an important landmark in 

 the history of botanical science, for it was the means of 

 inducing workers on the subject to rub their eyes, so 

 to speak, and reconsider the work they had accomplished 

 as well as the researches they had in contemplation. 



It is a little difficult to disentangle the various views 

 on plant anatomy and histology that were published 

 between 1830 and 1850, but two or three names stand 

 out prominently, and perhaps the simplest way. would be 

 for me to follow the work of these men in succession 

 and endeavour to estimate what additions they individu- 

 ally made to a knowledge of the subject. 



I must first make a brief reference to Meyen, who, 

 in 1830, wrote a Lehrbuch der Phytotomie. The views 

 expressed in this book compare very unfavourably with 

 those of Moldenhawer which I have already discussed 

 with you, and which were published nearly twenty years 

 before Meyen's textbook saw the light. Here we meet 

 again with many of the blunders made by the trio that 

 competed for the Gottingen Prize, and there are many 

 new ones added, belonging particularly to Meyen himself. 

 He thought that a spiral vessel was formed by first 

 laying down a spiral thread and then secreting a wall 

 round it afterwards. From such a vessel all the other 

 types annular, reticulate, and pitted were derived, but 

 while the spiral vessels transported sap their deriva- 

 tives carried air ! The laticiferous tubes are the highest 

 type of vessel and carried the " life sap " which circulated 

 through the plant like blood. It does not seem to have 

 occurred to these believers in latex as " life sap " that it 

 was necessary to explain how so many living plants had 

 no " life sap." Then again Meyen thought stomata 

 were cuticular glands, and that pits on the walls of cells, 

 fibres, etc., were not depressions but elevations ! After 

 these examples of Meyen's work I do not think you will 

 expect me to spend more time over him ; you may safely 

 class him along with Link, Rudolphi, and Treviranus. 



