360 
able time led to conclude inaccurately that Aphides con- 
tained a waxy substance coloured yellow by that compound. 
Such an instance of rapid and remarkable changes may be 
rare, but at the same time it serves to show the importance 
of our taking into consideration the possibility of its oceur- 
rence, even when circumstances are not so favorable for de- 
ciding the question. When exposed to the vapour of ether, 
though apparently killed, the insects sometimes revive, and, 
even if they do not, the Aphideine changes far more slowly, 
which may explain why bisulphide of carbon has a so much 
more poisonous action. 
Since it may, perhaps, be convenient for reference, I here 
subjoin a table of the character and position of the more 
important absorption-bands seen in some of the spectra 
roughly described in this paper, making use of the notation 
explained in a previous communication.’ 
TaBLE oF SPECTRA. 
Fraunhofer’ s lines, D is at 34 and ¥. at 73. 
1. As dissolved in water : 
Aphideine, alkaline . : , : P » eee 
a acid . ‘ : : : : .  6..7--8— 
The first mixed product : 
5b BR 
When alkaline varying as thus shown . ; -) 52 62 3 
When acid as a eg 
The second product 2 as 
2. As dissolved in ether, &c. : 
Avnidiratene th etter o a 
oa in ammoniacal solution of ether in water wi 83 
y in acid solution of ether in water 83 105 
Apbidiluteoleine in ether . G 95 
oe suspended in dilute alcohol with ammonia ‘ 63 
= ‘! a » citric acid 13 9 
1 “Qn Some Technical Applications of the Spectrum-microscope,” 
‘Quarterly Journ. of Micros. Science’ (N.S.), Vol. IX, pp. 358 and 359. 
