1818.] Death of Plants. 261 



tion, when the plant is full of life, though certainly sickening ; 

 as this is the cause of the swarm of insects that infect a sick 

 tree. We know that caloric and water contribute to increase 

 the nutriment of mankind, by rendering many vegetable mate- 

 rials innocuous, others digestible in the animal stomach, and it 

 appears particularly efficacious in promoting the saccharine 

 fermentation. Darwin supposes that it could contribute to ren- 

 der manures capable of being absorbed by vegetable roots in a 

 state of less decomposition than by the slow process of putrefac- 

 tion. But how the process could be shortened I cannot con- 

 ceive, since the earth suspends every effect. It is certain that 

 the saccharine process, begun in vegetables, will render them 

 more fattening to cattle than when given in their perfect state, 

 especially potatoes ; but then great care must be taken that it 

 does not go too far, or they putrefy. And it is not only that the 

 sweetness renders the plants more agreeable to the cattle, who, 

 therefore, eat more of them, but it corrects the acid effects of 

 the rind, and converts it into mucilage. The only deaths which 

 will cut short the process in plants, that I am acquainted with, 

 are those by lightning and frost. In these cases there is no 

 fermentation. The vegetable is killed in a moment, and putre- 

 faction and decomposition immediately succeed ; and the curious 

 appearance of plants thus destroyed, clearly exemplifies the 

 dreadful destruction that has ensued. I can perceive no differ- 

 ence in the two ; I have often seen potatoes and French beans, 

 when killed by frost, appear in the interior as if stirred with a 

 spoon ; the whole is destroyed, the vessels all broken, and the 

 muscles torn to pieces : putrefaction directly succeeds, and the 

 whole is decomposed ; and the matter is then drawn by its 

 various affinities to those juices which are of immediate use to 

 the plants which surround the decomposed matter; the water 

 with which it is mixed gives succour to all, and the food is assi- 

 milated with the vegetables around. To understand what is the 

 next process (when not directly absorbed by vegetable roots), it 

 would be necessary that the plants be confined, and not mixed 

 with the earth : this would at least show what are the steps 

 which bring them back to mould, to which a part must certainly 

 return. But I have particularly noticed that the vegetables are 

 so far from endeavouring to possess themselves of the putrefied 

 matter, though in great part decomposed, that the roots will 

 often turn from it, till all smell has passed away. Indeed all 

 plants are so susceptible of catching putrefaction, that nature 

 has undoubtedly guarded against this tendency : the plant, 

 therefore, must be completely disorganized before its parts can 

 mix with water, and be absorbed by other roots. How thoroughly 

 then doth this prove that no vegetable can be of use to others 

 till it is completely decomposed ; and how plainly does it show 

 the folly of burying young crops, whose crude and watery juices 

 J re still more unfit than those of older plants to administer to 



