622 Tjondon Hortimltnral Society and Garden. 



same species and variety have been planted in the same garden and the 

 same soil, but against walls with different aspects, anil differently situated 

 with rcaril to shade. The effect has been, not only a difference in the 

 growth and appearance of the tree, but also in the size, colour, and flavour 

 of the fruit which it producetl. The contrast between plants grown in 

 hot-houses with wooden sash frames, and tiiose grown in hot-houses 

 with iron sash frames, has been found equally striking ; the difference of 

 light between the two kinds of houses being as seven to twenty-seven, or, 

 sometimes, as three to twenty-three. Light is required at an early period 

 of vegetJition ; but, as its properties are to give strength ami flavour, it must 

 be admitted with caution, as it is sometimes injurious. Too much light 

 renilers the skin of fruits tough, and will make cucumbers bitter. Berard 

 of Montpelier found that the ripening of fruits is merely the turning the acid 

 which they contain into sugar, by exposure to the light ; and that too much 

 light and heat, before they have attained their proper size, w ill bring on pre- 

 mature ripening, and make them insipiil. 



The next subject upon which the professor proposed to treat, was the 

 multiplying of plants by cuttings. He had already, he observed, explained 

 the nature of a cutting. It is, in fact, a bud, containing within itself a 

 vital principle capable of developing in opposite directions, from a common 

 point, two cones, viz. the stem and the root. In making cuttings, ganleners 

 take care that each shall contain two or more nodes, or incipient leaf-buds; 

 but they generally take oft" any expanded leaves that may be on the stem, 

 lest the evaporation from their surface should be too great for the plant to 

 sustain, before fibrils to absorb moisture are formed from its roots ; for 

 this reason, also, it is usual to cover cuttings with a glass, and to set them in 

 the shade. Layers are portions of a plant induced to throw out roots 

 without being separated from the parent stem, by burying a leaf-bud in the 

 ground, and affording it an ample supply of warmth and moisture. The 

 branch thus treated is generally split, so as to prevent the return of the 

 .sap, and thus to force tlie bud to throw out radicles, (irafting may be 

 called planting a bud in a tree, instead of in the ground ; and inarching 

 bears the same resemblance to grafting, as layers do to cuttings. Neither 

 grafting nor inarching can be jjerforraed with any prospect of success, 

 luiless the trees to be united have an affinity to each other ; and, even 

 when they have, some plants unite more readily than others. It is very 

 difficult to make a pear grow on an apple, but it will graft freely on a iiaw- 

 thorn or a (juincc. Care must be taken, however, in all cases, that the 

 parts are ])roperIy joined, so that the edges of the corresponding tissue may 

 come in contact, or no union will take place. 



Pruning is a branch of horticulture that requires great skill. Different 

 parts of a tree produce fruit; and it is necessary to know these, to be able 

 to prime with advantage, as an ignorant i)runer might make the most 

 fertile trees sterile, by cutting off' the only parts likely to produce fruit. 

 In some trees, fruit grows only on the extremity of the branches, ami on 

 others on the spurs. The use of |)runing fruit trees is to i)revent their 

 riuining too much to wood. Fruit and forest trees, of course, require (juite 

 different management in this respect; as the object, in one case, is to make 

 wood, and, in the other, to check it. Too nnich pruning is, however, bad 

 for both. The professor here observed that he had intended to give some 

 directions resjjecting the best methods of saving seed, but he found that 

 time would not permit. 



The scales of bulbous plants contain not only undeveloped leaves, but 

 nourishment for the stem. It is extremely difficult to propagate bulbs in 

 this country ; and hyacinths, &c., imjjorted, rarely retain their beauty after 

 the first season. This the professor attributed to the injury sustained by 

 their leaves, either from frosts or want of care. In Holland, the leaves 



