THE LEAF. 37 



(3) Balfour's " Manual of Botany." ' Sap,' yes, at last. " Ar- 

 ticle 257. Course of fluids in exogenous stems." I don't care 

 about the course just now : I want to know where the fluids 

 come from. "If a plant be plunged into a weak solution of 

 acetate of lead," I don't in the least want to know what hap- 

 pens. "From the minuteness of the tissue, it is not easy to 

 determine the vessels through which the sap moves." Who 

 said it was ? If it had been easy, I should have done it my- 

 self. " Changes take place in the composition of the sap in 

 its upward course." I dare say ; but I don't know yet what 

 its composition is before it begins going up. " The Elabor- 

 ated Sap by Mr. Schultz has been called ' latex.'" I wish Mr. 

 Schultz were in a hogshead of it, with the top on. " On ac- 

 count of these movements in the latex, the laticiferous vessels 

 have been denominated cinenchymatous." I do not venture 

 to print the expressions which I here mentally make use of. 



15. Stay, here, at last, in Article 264, is something to the 

 purpose: "It appears then that, in the case of Exogenous 

 plants, the fluid matter in the soil, containing different sub- 

 stances in solution, is sucked up by the extremities of the 

 roots." Yes, but how of the pine trees on yonder rock ? Is 

 there any sap in the rock, or water either? The moisture 

 must be seized during actual rain on the root, or stored up 

 from the snow ; stored up, any way, in a tranquil, not actively 

 sappy, state, till the time comes for its change, of which there 

 is no account here. 



16. I have only one chance left now. Lindley's "Introduc- 

 tion to Botany." ' Sap,' yes, ' General motion of.' IL 325. 

 " The course which is taken by the sap, after entering a 

 plant, is the first subject for consideration." My dear doctor, 

 I have learned nearly whatever I know of plant structure from 

 you, and am grateful ; and that it is little, is not your fault, 

 but mine. But this let me say it with all sincere res'pect 

 is not what you should have told me here. You know, far 

 better than I, that ' sap ' never does enter a plant at all ; but 

 only salt, or earth and water, and that the roots alone could 

 not make it ; and that, therefore, the course of it must be, in 

 great part, the result or process of the actual making. But I 



