6 THE PLANT. 



were allowed to vegetate in water, imparted to the water, 

 after a week's time, a yellowish tint, a smell like that of 

 opium, and a harsh taste : whereas when the root was 

 cut off at the stalk and both were placed in water, no 

 such substances were given off as those which the entire 

 plant had yielded. 



Lettuces and other plants, when taken out of the 

 ground, and, with their roots previously washed clean, 

 are allowed to vegetate in blue htmus tincture, will con- 

 tinue to grow in the hquid, apparently at tlie expense of 

 the constituents of the lower leaves, which wither away. 

 After tln-ee or four days the htmus tincture assumes a red 

 colour, which, however, disappears again upon boihng the 

 fluid : this would seem to indicate that the roots had given 

 off carbonic acid. If the plants are left longer in the 

 litmus tincture, the latter suffers decomposition, and be- 

 comes neutral and colourless, while the colouring matter, 

 separating in flakes, gathers round the fibres of the 

 roots. 



The developement of a plant depends upon its fii^st 

 radication, and the choice of proper seeds is therefore of 

 the highest importance for the future plant. A crop of 

 the same wheat, reaped in the same year, and from the 

 same field, will exhibit differences in the size of the 

 grains, some being larger, others smaller; and among 

 both kinds, some when broken up will present a mealy, 

 others a horny appearance, the one being more, the others 

 less completely developed. The cause is this — that the 

 stalks in the same field do not all shoot into ear and 

 flower at the same time, and that some of them produce 

 seeds much more maturely than others : hence the seeds 

 of the one are far more developed, even in unfavourable 

 weather, than the seeds of the others. A mixture of 

 seeds unequal in their developement, or differing in the 



