38 
ON THE CULTURE OF THE MOMBIN, HOBO, &c. AS TABLE FRUIT. 
Mr. Main thus proceeds to describe his theory of a vital membrane, called by him 
Indusium. " There is a distinct member situated between the liber and alburnum. 
So that if waxed paper be placed within this membrane, the new alburnum will be 
formed on the outside ; but if placed on the exterior side, the new deposit will be 
invariably found within it, and just where it would have been had no paper been 
inserted. 
" Cambium,'" according to Dr. Lindley, " is a viscid secretion, which in the 
spring separates the alburnum of an exogenous plant from the liber. It is free 
vegetable mucilage, out of which the new elementary organs are constructed, 
whether in the form of vessels or woody tissue, or of cellular tissue of the medullary 
system, whose office is to extend the medullary plates, and maintain the commu- 
nication between the bark and central part of the stem." 
Here then we must recur to the grand question, is the Cambium a vitalised 
membrane, identical with the Indusium or not? Cambium is present when the 
bark detaches ; it is the organised matter that causes the junction of a graft with its 
stock, and which, at least, contains the germs of buds, leaves, and all progressive 
developments ! 
ON THE CULTURE OF THE MOMBIN, HOBO, ZANZEE, AND 
OTHER SPECIES OF HOG PLUMS, 
AS TABLE FRUIT. 
In this improving and scientific age it might be well to call particular attention 
to Tropical Fruit Trees, a class of plants, which although for the most part orna- 
mental, and many long inhabitants of our stoves and greenhouses, have certainly not 
hitherto received that attention to their culture, which the merits of many of them 
deserve. It is true Guavas, Mangos, Rose-Apples, Granadillas, Loquats, and some 
others, have yielded their fruit in several parts of this country, but their cultivation 
for this purpose has been too limited, and is too little understood by the generality 
of gardeners to be considered an important item in garden operations. 
The low price of glass, however, in the present day, and the gigantic structures 
which have been built, and are at present in course of erection, in different parts of 
the country, will probably lead to results of the most important kind. A few years ago 
who would have ventured to assert that the various species of Banana would have 
formed any part of the dessert of our tables ? Yet such is the case, and that by very 
simple cultivation. And who would venture to deny that in a few more years our 
tables will not daily exhibit splendid specimens of Mangos, Mangosteens, Sapota 
Plums, Lee Chees, Blimbings, Custard Apples, and many others, which, except as 
they are eaten in their native countries, or are brought here in a partly dried state, are 
all but unknown, except by name, to the greater part of the gardeners of this country ? 
Already some of these novelties have begun to exhibit themselves in the large 
