354 LECTURE ON SPRING FLOWERING PLANTS. 



means new. It was known to the Romans. Pliny tells us 

 that they used to obtain Roses at Rome before the 

 natural season by watering the plants with warm water 

 so soon as the buds were visible. The Romans in the 

 reign of Domitian had undoubtedly abundance of Roses 

 in winter. It is probable that the art of forcing was 

 borrowed from the Egyptians, and first practised at 

 Rome in the time of Martial, the famous epigrammatic 

 poet, who ridicules the Egyptians for still sending them 

 Roses when they had plenty of their own, and asks them 

 to send corn instead. Dr Deslongchamps relates, on the 

 authority of Seneca, that the Roman gardeners had at this 

 time found out the means of constructing hot-houses, 

 which they heated with tubes filled with hot water, and 

 thus induced Roses and Lilies to flower in December. 

 In dealing with this subject it seems desirable to show, in 

 the first place, the principles on which success depends, 

 and afterwards to describe the most important details of 

 cultivation. 



The cultivator should never forget that a plant is 

 a living organism. There are the root, the stem and 

 branches, the leaves, the flowers, the fruit. The sap which 

 traverses all these parts is analogous to the blood in 

 animals. While the plant feeds principally by the roots, 

 and can receive food only in a fluid state, it feeds also by 

 the leaves, which breathe, digest, and perspire. The 

 leaves of plants perform functions analogous to those of the 

 lungs, digestive organs, and skin of animals. The roots of 

 a plant absorb moisture from the soil in which they grow. 

 This moisture or water containing various matters in 

 solution we call sap, which passes in a crude state through 

 the stem and branches to the leaves, where it undergoes 

 certain modifications. It is then returned into the general 

 circulation in an altered and matured condition, suitable 

 to the particular wants of the plant. 



Further, plants have two periods of comparative rest, 

 arising from the alternations of day and night, summer 



