PROCESS OF GEEMINATION. 23 



of litmus paper fastened on the inside, the paper is red- 

 dened, often after a very short time, owing to the dis- 

 engagement of acetic acid : the most abundant and 

 rapid evolution of free acid was found to take place in 

 the germination of cruciferous plants, cabbage, and 

 rape-seed (Becquerel, Edwards). Certain it is that the 

 fluid contents of the cells of the roots, as well as the sap 

 of most plants, have an acid reaction, from the presence 

 of a non-volatile acid ; the sap of the young spring 

 shoots of the vine yields, upon evaporation, an abun- 

 dant crystallization of bitartrate of potash. 



By the experiments of Decandolle and Macaire, 

 which have not yet been controverted, it was shown 

 that vigorous plants of C/iondrilla muralis and Phaseo- 

 lus vulgaris which had been taken from the ground, 

 with their roots, and 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 

 gound, and, with their roots previously washed clean, 

 are allowed to vegetate in blue litmus tincture, will 

 continue to grow in the liquid, apparently at the ex- 

 pense of the constituents of the lower leaves, which 

 wither aw r ay. After three or four days the litmus tinc- 

 ture assumes a red colour, which, however, disappears 

 again upon boiling the fluid : this would seem to indi- 

 cate that the roots had given off carbonic acid. If the 

 plants are left longer in the litmus tincture, the latter 

 suffers decomposition, and becomes neutral and colour- 

 less, while the colouring matter, separating in flakes, 

 gathers round the fibres of the roots. 



The developement of a plant depends upon its first 

 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 



