373 
mentation, and is continued when the beer is kept in barrel. 
Still, however, it does not seem to depend simply on fer- 
mentation, since no such change occurs when fermented on a 
small scale ; and, therefore, it may perhaps be due to deoxi- 
dization, which would be more likely to take place in a large 
quantity less exposed to air. 
If in any case it were desirable to ascertain whether or no 
any mixed liquid contained beer, the various reactions with 
the reagents already mentioned might enable us to form a 
very decided opinion when other tests failed ; but so much 
would depend on the circumstances of the case that no general 
rule could be given. 
On Some Adulterations of Malt Liquors. 
I have made very many experiments in order to ascertain 
how far the spectrum method can be employed in detecting 
adulterations in beer. Many of the substances used are added 
in such small quantities, and impart so little colour, that there 
seems to be no chance of discovering them by their spectra. 
I have chiefly directed my attention to those employed as sub- 
stitutes for hops, such as picric acid, gentian root, calumba 
root, and the entire plant of Ophelia chireta, commonly known 
by the more simple name of chiretta. So far I have not been 
able to detect any difference between the colouring matter of 
gentian, or chiretta, and hops. They all give the same re- 
actions and spectra with the various reagents, or at least so 
nearly the same that there appears to be no chance of detect- 
ing them in the presence of the colouring matter of wort or 
beer. Calumba root, however, contains two colours, one of 
which is quite different from any that should occur in genuine 
malt liquors. The exterior part of the root is yellow, and 
water extracts from it a bright yellow' colour. The interior 
part is browner, and does not contain this yellow, but a 
browner colour, which also occurs to some extent in the outer 
layer. On evaporating the aqueous solution to small bulk and 
redissolving in alcohol this brown colour is left insoluble, 
but the bright yellow colour remains in the alcohol, in a 
curiously turbid condition. The brown colour appears to be 
identical with that found in liquorice, and could not be 
detected by any of the reagents ; but the yellow colour may 
be recognised, if beer has been adulterated by a moderate 
amount of calumba root. When dissolved in water or alcohol 
it is a very clear, bright yellow, but gives no well defined 
spectrum. Ammonia makes it slightly orange, and when dis- 
solved in sulphuric acid it is the same bright yellow as in 
water. Oxidizing reagents, such as hypochlorite of soda, pro- 
