426 ON THE JUICE OF THE SUGAR-CANE. . 
the acetate of lead be used to determine the quantity of these organic 
substances, we must then take account of the difference resulting from 
the action of this salt on the carbonates, chlorides, and sulphates of the 
juice; otherwise we shall be acting on a first product of too high a 
figure. The basic acetate has been employed ; but from the precipitate 
obtained there has been deducted the weight of the quantity of those 
insoluble salts carried down at the same time with the vegetable mat- 
ter. In the general table already given will be found the proportion of 
such matter for 1,000 grammes of juice from canes taken in different 
conditions of age, climate, &c, and I have estimated the average at 3*5 
thousandths of the weight of the cane-juice. It has also been seen that 
pressure augments the quantity in the juice, which may thus occasion 
additional trouble to the manufacturer. Whatever kind of cane be 
examined, it is always in the uppermost portion that the largest amount 
of vegetable matters is met with. Those canes which are not com- 
pletely developed, do not generally contain a larger quantity of it than 
the ripe canes, it we compare the weight of these substances to that ot 
the juice, and not to that of the total matters dissolved as some writers 
on the subject seem to have done. If we group these different materials 
into three categories, the first embracing what has already been described 
under the name of granular matter ; the second, the albumen of the 
juice or that substance capable of coagulation by heat ; and the third 
one, or more azotized substances which can only be cc agulated by alcohol 
and the metallic solutions, it will be found that they are on the average 
in the following proportions : — 
Granular matter 0-287 
Albumen 0-076 
Other vegetable substances .... 0-637 
and as they enter in totality into the juice for thirty -five ten-thousanths 
it results therefrom that one hundred parts of this liquid contain : — 
Granular matter 0100 
Albumen . . . . . r . . 0-027 
Other vegetable substances . • . . . 0*223 
0-350 
The albumen found in cane-juice coagulates at about 80° and is pre- 
cipitated by powerful acids, without being re-disfiolved in any sensible 
manner by an access of the reacting substance. After this albumen is 
separated by heat, there remains in the juice a complex organic matter 
which can be precipitated by alcohol and by the neutral acetate of lead, 
and which is very soluble in alkalis and acids, and even in tannic acid. 
Separated and purified by several precipitations in alcohol, this substance 
is without smell or taste, white, amorphous, without influence on polar- 
ised light, giving out ammonia when heated with lime or potash, and 
