294 THE FLORIST AND 



SOME PRINCIPLES OF VEGETABLE PHYSIOLOGY, BEARING 

 ON THE CULTURE OF PLANTS. 



BY PROFESSOR TV. H. DE VRIESE, OF THE UNIVERSITY OF LEYDEN. 

 (Translated from the Dutch.) 



A plant cannot live, but much less grow, by means of water only ; how- 

 ever, water performs here a very important service, for it conveys much of 

 that which must be a means of nourishment to the plant. The substances 

 under ground, whether they have their origin from dissolved remains of 

 plants or animals, or are of an earthy nature, contribute, in fact, to the 

 formation and development of the plants substances which are found in 

 ashes of burned plants. Potash and soda, e. g., form a principle of the 

 composition. The former substance is prepared in great quantities from 

 wood ash ; the soda is manufactured from many plants found on the sea- 

 shore. Lime, one of the substances which are most scattered through the 

 whole of nature, is likewise present in almost all plants. Investigation 

 proves to us that in plants, many other substances known to us as solid 

 bodies exist ; the water dissolves those substances either as such or united 

 with other bodies, and so they penetrate the plants. Thus water is chiefly 

 the fluid through which matter is conveyed : but when we observe how great 

 a mass of such substances exists in plants, and how small a quantity of them 

 maybe dissolved in the water, if, on account of too great a degree of den- 

 sity, it is not in a state to penetrate the plants, then we must be convinced 

 of the immense quantity of water which must pass through a plant during 

 its whole life, before it has attained its full delopment and finished its whole 

 growth. 



If the use of the evaporation to the plant must be measured by the degree 

 in which it takes place, Ave may be sure that it is indeed of the greatest 

 service to its vegetation. We can prove this by remarkable examples. 



At the end of the seventeenth century, an English naturalist, Stephen 

 Hales, wrote a book, entitled "Vegetable Statics," in which he described the 

 following observation : A Sun-flower, which was 3 J feet high, evaporated dur- 

 ing a very hot day, 1 lb. 14 oz. of water. The evaporation averaged per 

 day, 1 lb. 4 oz. He observed, that plants with hard wood and evergreen 

 leaves evaporate less than those which fall off, such as Cabbage leaves, leaves 

 of Apple trees, and others. However, it is not easy to make such experi- 

 ments, for the evaporation of the soil in which the plants are, must not be 

 computed : and if the amount of the evaporated substance is to be exactly 

 determined, it is necessary to enclose the plants. Attention must be paid 



