INTRODUCTION. 25 



THE SPLITTING OF FRUIT OSMOSIS. 



The principle of osmosis, or the movement of fluids through the membranes of fruit, 

 is not sufficiently comprehended by cultivators, including the majority of gardeners, and 

 it is much too important to be overlooked here. It is admitted that moisture in the 

 atmosphere is essential when fruits are swelling, and when the heat vapour is consider- 

 able they increase in size with great rapidity. This is not in consequence of moisture 

 supplied by the roots alone, for, no matter how ample this might be, the growth of the 

 fruit would be slow, and it could not attain a large size in a dry atmosphere. This is 

 well displayed in the stunted growth of cucumbers under arid surroundings, and their 

 almost visible movement when highly heated air is heavily charged with moisture. 

 This fact is so well known that some cultivators of this crop keep the ventilators closed 

 to prevent the escape of moisture from the structures. They do not know why 

 the confined vapour has the desired effect. It is because the moisture passes into the 

 fruit by endosmotic action, or the transmission of the thin fluid in the air to the denser 

 in the fruit. This is the case in all fruits, whether grown under glass or in the open 

 air, though a too confined atmosphere would be distinctly injurious to all that will 

 have attention in these pages. The cucumber, being used as a vegetable, will not 

 be included, and is only cited as illustrative of an important element in the swelling 

 of crops. 



Fluids are continually passing through the substances of plants and fruits, the 

 thin liquid to the denser. When the movement is outwards the action is described as 

 exosmose ; when inwards, from the air, endosmose. The endosmotic action may be 

 demonstrated by means of a glass tube containing a thick liquid, such as syrup, the 

 end of which is tightly covered with parchment or a piece of bladder, then placed 

 in water, which will enter through the membrane and cause the fluid to rise in the 

 tube. This is exactly what takes place in fruit, and the epidermis, or skin, being 

 elastic when young, or during the growing period, the fruit enlarges in consequence. 

 A moist, genial atmosphere is requisite, with other essentials, during that period, for 

 the production of fine fruit. Now we pass to another important phase of the question. 

 When fruit has attained its full size and become ripe, the skin loses its elasticity, and 

 if the atmosphere is too moist the thin vapour rushes through the membrane to the 

 thicker in the fruit, which splits. In that way crops of ripe gooseberries, cherries, 

 and plums, in the open air have been ruined during drizzling rains, and a moisture- 



VOL. I. B 



