Pure and Mixed Linseed- Cakes. 
39 
Similar instances, if necessary, might be quoted in further 
illustration of the fact that a proximate analysis in itself is insuf- 
ficient to determine whether a cake is poisonous, or a pure, or an 
adulterated linseed-cake. It must not be inferred, however, from 
this remark, that it is altogether useless to submit a cake to a 
proximate analysis, for in not a few cases such an analysis 
affords useful hints to the examiner, and supplies him with posi- 
tive evidence that a cake is adulterated. 
Thus linseed-cakes adulterated with ground-nut' and cotton- 
cake, or rice-husks, olive-cake, cocoanut-fibre, and other materials 
abounding in woody matter, on analysis furnish a much higher 
percentage of woody fibre than occurs in genuine cake of fair 
average quality. 
Again, if a cake is largely adulterated with starchy mill- 
refuse, its analysis generally shows a deficiency in oil and albu- 
minous compounds, and by appropriate tests the presence of 
starch, which is not a normal constituent of linseed, can be demon- 
strated. Or if a cake is made from very dirty seed, or is mixed 
with ground plaster of Paris, which I might have mentioned in 
the list of adulterating materials, for I found ground plaster of 
Paris on several occasions in oil-cakes, the analysis of the 
adulterated cake will show an unusually high percentage of sand, 
or the presence of sulphate of lime (plaster of Paris) or other 
earthy or mineral matter that may be present in much larger 
quantities in the adulterating materials used in the manufacture 
of the cake than in genuine linseed-cake. Linseed-cakes which 
are adulterated with bran or pollard, or with rice-meal are gene- 
rally poor in oil and albuminous compounds. This is seen in 
the following analysis of cakes, all adulterated with bran, pollard, 
and similar starchy mill refuse. 
Table XII. — Composition of Linseed-Cakes adulterated with Bran, 
Pollard, and Eice-Meal. 
No. 1. 
No. 
2. 
No. 
3. 
No 
4. 
13-32 
9 
•92 
13 
52 
12 
-12 
Oil 
9-26 
9 
-88 
9 
02 
8 
•27 
*Albumiiious compounds (flesh-forming 1 
21-9-t 
23 
25 
23 
64 
25 
•87 
Starch, mucilage, and digestible fibre 
38-46 
35 
-46 
33 
87 
31 
•37 
10-96 
13 
-73 
12 
08 
12 
•92 
6-06 
7 
76 
7 
87 
9 
•45 
100-00 
100 
00 
100 
00 
100 
•00 
3-51 
. 3- 
72 
3' 
"6 
4- 
14 
f Containing sand 
1-64 
2* 
45 
3- 
43 
37 
