4£ 



scientific research ; but the facts now brought forward proved 

 that something more was requisite than a knowledge of the 

 chemical constituents of the soil ; for it appeared that while 

 crops of clover had failed on soil which apparently contained 

 every element of nutrition, they had flourished upon land that 

 was inferior in this respect ; and it followed that the mechan- 

 ical condition of the soil, i.e. its compact or loose state, was a 

 matter to be attended to in considering the causes of fertility 

 and barrenness. He had lately seen an instance corrobora- 

 tive of Mr. Thorp's views, where a sandy soil had become 

 compact from the constant treading of horses, and now for 

 the first time was covered with a luxuriant crop of white 

 clover. 



Dr. Daub EN Y then rose and said, — Ten years ago, when 

 he came from Geneva, he was fully impressed with the truth 

 of the theory that every plant excretes a certain substance 

 which is poisonous to itself, though it may prove nutritious to 

 others. He had made experiments, and although the result 

 arrived at showed that a deterioration takes place in ground 

 not manured, yet, it did not appear that in the generality of 

 crops the excretions which plants throw out are poisonous. 

 He would not dwell on the explanation offered by Mr. Thorp, 

 but he might mention one circumstance with regard to clover, 

 which was, that some planted near a margin of box had 

 grown luxuriantly. It would seem that it was not owing to 

 the soil, but that it was owing to a nutritious matter which 

 had been supplied by the box. He would just allude to one 

 effect which might confirm one part of Mr. Thorp's state- 

 ments, respecting the necessity of warmth for a reduction in 

 the food of animals. Two swarms of bees had been put 

 together, and the mutual heat communicated to each other 

 was such, that they actually consumed less food than one 

 swarm would have eaten if they had been separate. He 

 would conclude with these observations, and with expressing 



