40 LIFE OF 



actual danger, he appeared to be, till I had talked to him for 

 some time in a friendly and familiar way. With very kind 

 remembrances to all, 



" Ever your affectionate father." 



In the summer of 1827, Mr. Knight had the gratification of 

 receiving a visit from Monsieur Dutrochet, with whom he had 

 long held an intercourse by letter, though they had not previ- 

 ously met. The extract given below from a letter to Mr. 

 Williams, relates to this visit; 



" We came here (Downton) from London in a single day, or 

 we should have had great pleasure in spending a day at Pit- 

 maston. I brought with me my French correspondent, Mons. 

 Dutrochet, who I mentioned to you as the discoverer of the extra- 

 ordinary circumstance that animal and vegetable membrane, 

 which under ordinary circumstances are impervious to water, 

 readily admit that fluid to pass through them when their oppo - 

 site sides are in contact with a fluid of greater density, or in some 

 instances possessing different chemical powers ; and the facts 

 he had advanced render it doubtful whether any mechanical 

 agent is at work in raising the sap in trees, except the mem- 

 brane, which separates the cells from each other, which are 

 excited to act by some power, probably chemical, in the sap. 

 M. Dutrochet spent a fortnight here, during which we made 

 some experiments together, and investigated the hypotheses of 

 different writers. He travelled 550 miles, and back again, with 

 no further object than to have an opportunity of conversing 

 upon the subject of vegetable physiology. I found him a very 

 intelligent and generally well informed man, and he returned a 

 very zealous horticulturist. The inhabitants of his vicinity, the 

 neighbourhood of Tours, appear to be extremely ignorant of 

 horticulture, and to know nothing of varieties of fruit of any 

 kind beyond those described by Duhamel." 



Mr. Knight's time was divided between philosophical and 

 horticultural investigations, and the fulfilment of the duties of 

 a country gentleman. He had ceased to occupy any land him- 



