50 Impot'tance of Cleanliness to Plants. 



surface is clogged by dirt, of whatever kind, their breathing 

 is impeded or prevented. Plants perspire by their leaves ; 

 and dirt prevents their perspiration. Plants feed by their 

 leaves ; and dirt prevents their feeding. So that breathing, 

 perspiration, and food, are fatally interrupted by the accumu- 

 ' lation of foreign matters upon leaves. Let any one, after 

 reading this, cast an eye upon the state of plants in sitting 

 rooms or well-kept greenhouses ; let them draw a white 

 handkerchief over the surface of such plants, or a piece of 

 smooth white leather, if they desire to know how far they are 

 from being as clean as their nature requires." 



The importance of more attention to the cleanliness of 

 planits has been forcibly brought to mind by reading an ac- 

 count of the experiments of M. Garreau, on the perspiration 

 of plants ; an abstract of which was given in the Gardeners^ 

 Chronicle of last year. They show, in the most satisfactory 

 manner, that one of the greatest sources of a healthy veg- 

 etation is a clean foiiage ; and that where this cannot be 

 effected by rain, it is essentially necessary that it should be 

 accomplished at the hands of the cultivator. 



M. Gaxreau's experiments, it will also be noticed, confirm 

 the opinions of many amateur and practical men, that soap 

 and water are of imore effect in enabling the leaves to carry 

 on their absorptive powers than clear water alone. M. Gar- 

 reau found this to be to the extent of nearly one half. A fig 

 leaf, which had been washed with soap, absorbed 90 parts, 

 while, after a simple drenching with Avater, it took up only 

 one half. 



The result of all these experiments show that all plants, 

 when housed up for six months, as they are in our climate, 

 require not only repeated syringings during that time, but 

 they require even more if we would keep them in the most 

 robust condition. In particular, should camellias, oranges, 

 daphnes, and similar broad-leaved plants, be washed once or 

 twice in the winter with soap and water, each leaf receiving 

 a careful sponging on its upper as well as under surface. 

 If this, with due attention to a moist atmosphere and wa- 

 tering, was attended to, we should hear less complaint of 

 sickly collections of plants : — 



