COLOUR-TESTS FOR STRYCHNIA, ETC. 
793 
strychnia, nor any succession of colours any way resembling 
them, so that I am now in a condition to assert that strychnia 
stands alone among sixty-six analogous compounds in the 
reactions which it gives with sulphuric acid followed by the 
bichromate of potash. 
Mr. Jenkins (as will be seen in the table published by him 
in the Chemical News for October 6th, 1860) arranges his 
reactions in two columns. The first column displays the 
effect produced by strong sulphuric acid; the second, the 
changes of colour caused by the addition to the acid solution 
of the bichromate of potash. 
Now, this table affords an excellent illustration of the 
absence of method and logical arrangement. The substances 
operated on evidently took their places as they chanced to 
come to hand. Strychnia itself has to be sought out, and sub¬ 
stances which give coloured reactions with sulphuric acid find 
themselves in contact with others that give a negative result. 
And yet the table seems to court the attention of lovers of 
method and logical order. It is almost impossible to keep 
one’s hands off it. At least, one would like to place the sub¬ 
stances which are not coloured by sulphuric acid by them¬ 
selves, and those that are coloured also by themselves. I 
have undertaken this work of tabulation, and, on inspecting 
the result, am seized with the same desire to resume the 
work of arrangement. In both groups there are substances 
which yield with bichromate of potash the same colours. 
Why should not these similar reactions be bracketed to¬ 
gether? This, accordingly, I have carried into effect, and 
the result is a splitting up of the fifty substances into several 
groups of such moderate dimensions, that a man given to 
tabular analysis can scarcely resist the additional temptation 
to try whether some modification of the tests themselves, or 
some additional tests, or both together, may not lead to a 
successful separation and elimination of each and all the sub¬ 
stances contained in the table.* I now proceed to lay before 
you in a tabular form the results of a very laborious experi- 
* In the lectures given at the College of Physicians Mr. Jenkins’s 
original table, and the two tabular arrangements alluded to in the text, were 
sent round. These tables were the more freely used as illustrations of 
a want of logical arrangement, as the author evidently did not aim at 
diagnosis, but only at the distinct ascertainment of the peculiar and cha¬ 
racteristic reactions of strychnia. The remarks in the text were not, 
therefore, intended in any respect as a censure of Mr. Jenkins for not 
adopting an arrangement which, for his purpose, was unnecessary. I may 
add, that his table comprises several substances which will not be found in 
the tables I am about to submit. I mean such substances as the kinic and 
kinovic acids, and such animal products as urea and uric acid. 
xxxv. 51 
