III. THE LEAF. 55 



1 6. I have only one chance left now. Lindley's 

 "Introduction to Botany." 'Sap,' — yes, — 'General 

 motion of.' II. 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 sin- 

 cere respect — 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 will read now, patiently; for I know you will tell 

 me much that is worth hearing, though not perhaps 

 what I want. 



Yes ; now that I have read Lindley's statement 

 carefully, I find it is full of precious things ; and 

 this is what, with thinking over it, I can gather for 

 you. 



17. First, towards the end of January, — as the light 

 enlarges, and the trees revive from their rest, — there 

 is a general liquefaction of the blood of St. Januarius 

 in their stems ; and I suppose there is really a great 

 deal of moisture rapidly absorbed from the earth in 

 most cases ; and that this absorption is a great help 



