Pure and Mixed Linseed- Cahes. 
7 
assured by persons well acquainted with dealings in genuine 
linseed that the siftings from it are mostly used for producing 
cheap linseed. Occasionally barges laden with the siftings are 
sent out a little way to sea, to meet ships having on board linseed, 
and coming from one of the ports in the North, An amalga- 
mation of the siftings with the linseed is effected on the high 
sea, and the mixture, containing a greater or less quantity of 
siftings, is then imported, and sold as linseed " genuine as 
imported." A good deal of so-called genuine linseed-cake is 
made from such seed. It is well to bear in mind that a gua- 
rantee which describes a cake as made from linseed, " genuine 
as imported," in point of fact is no guarantee at all, for it is a 
well-known fact that very dirty linseed, not unfrequently con- 
taining more than half its weight of foreign weed-seeds, is 
freely imported into Hull and other ports. 
Some of the weed-seeds which compose the bulk of the 
siftings and screenings from linseed, like the seeds of the 
purging flax, wild mustard, and wild radish, possess decidedly 
injurious properties ; others, like darnel and corn-cockle seed, 
are reputed to be unwholesome, and the remainder have no 
great Aalue as feeding materials, while many give a bad flavour 
to the calce. 
Amongst the weed-seeds in commercial linseed I have found 
the following : — 
1. Rape-seed [Brassica Rapa). 
2. Indian rape (^Shiapis plauca). 
When rape-seed occurs in linseed-cake in appreciably large 
proportions, it imparts to the cake a somewhat pungent and 
turnip-like flavour. From linseed-cake adulterated with rape- 
seed, portions of the brown cuticle may easily be separated, and 
these examined under the microscope will exhibit the structure 
represented in the accompanying woodcuts. The proportion of 
nitrogenous compounds in two samples of rape-seed 1 found to 
amount to 18'50 per cent, in best Indian rape-seed, and 19'43 in 
English rape-seed. 
3. Red or wild mustard, charlock or ketlock (Sinapis arvensis). 
4. White mustard (Sinapis alba). Red and white mustard, 
on digestion with water, produce highly pungent essential oils. 
Linseed-cake contaminated with mustard, when made into jelly 
with water, and allowed to stand for an hour or thereabout in a 
warm place, develops the peculiarly pungent smell of oil of 
mustard. 
The cuticle of mustard-seed resembles in appearance that of 
rape. It may, however, be distinguished from the latter by the 
hexagonal cells which appear quite marked under the microscope, 
