678 
The Formation of Coal. 
[Odtober, 
position of these elements, at present but imperfectly 
defined, such as chlorophyllus gum, the gelatinous sub- 
stances of fruits, which are found in a great number of 
tissues, and which certainly play an important part in the 
vegetable organisation ? Lastly, will it be possible, when 
all these substances are understood, to determine under 
what influences the tissues of these vegetables are capable 
of being transformed into fossil fuel, such as lignite, coal, 
and anthracite ? 
Taking this programme as the basis of my researches, I 
shall make a rapid survey of those investigations by which 
I sought to establish the nature and composition of those 
substances forming the skeleton or framework of vegetable 
matter. 
The organic elements which I first examined were but 
little known. Their characteristic property is to produce, 
under the influence of fermentation or by the aCtion of 
chemical reagents, a series of gummy and gelatinous sub- 
stances. They may be confounded with the cell-walls 
themselves when they are merely subjected to microscopical 
examination. They often join the cells together, as is 
shown in the tissue forming the pith of the elder tree. I 
have demonstrated that the gelatinous substances of vege- 
tables are derived from a primal insoluble substance which 
I have named pectose , and which, by successive polymerical 
transformations, forms at first gummy substances, then 
gelatinous bodies, and lastly a soluble acid, the strength of 
which may be compared with that of the acids found in 
fruits. All these transformations are produced during the 
growth of the vegetation. 
M. Fremy then undertook the investigation of the pro- 
perties and nature of the stable and fixed bodies forming 
the fibres, the cells, and the duCts. From these researches 
it results that the vegetable framework is not so simple as 
was commonly supposed. It is not constituted of a single 
substance, the cellular variously incrusted with foreign sub- 
stances, but of several kinds of isomeric cellular substances. 
In addition to this, a very important body is also met with, 
which differs from the cellular in respedt to its composition 
and properties, a body which runs abundantly in the du< 5 ts, 
and which M. Fremy has for this reason called vasculose. 
It is this substance which causes the hardness and density 
of the ligneous tissues to vary according to the proportion 
in which it is contained. Oak may contain 30 per cent of 
it, and as much as 50 per cent may be found in nutshells. 
The vasculose is placed between the walls of the fibres and 
