950 
THE PH ARM ACS UT [ CAL JOURNAL AND TRANSACTIONS. 
[May 31, 1873. 
effect of certain reagents is tried, and if any effect 
upon tire spectrum is produced, the spectrum is 
charted as before. 
Thus, the normal spectrum of a certain specimen 
of cantharides is that charted in No. 3. The addition 
of hydrochloric acid removes the band from the 
orange and lowers the absorption of the violet. Pro¬ 
tosulphate of iron restores the violet absorption but 
does not restore the band. The alcohol solution of 
twenty-eight hours’ maceration does not give the band 
in the orange, but in forty-eight hours more this band 
is visible. If metallic sodium be added to the ethereal 
solution as in No. 3, and water added when the violent 
action of the metal has ceased, the water carries down 
all the colouring matter, but yields it again on the 
addition of any oxidizing agent. Caustic potash 
added to the alcoholic solution removes the band by 
continuing the absorption to the red end (that is, the 
No. 1. Gibson’s (old) Can- 
tharides.j 
No. 2. Elm (deoxidized). 
No. 3. Earle’s (Fresh) Can¬ 
tharides. 
No. 4. Privet leaves (old). 
No. 5. Southall’s (rather old) 
Cantharides. 
No. 6. Lilac; full grown 
young leaves. 
No. 7. Gregory’s (old) Can¬ 
tharides (oxidized). 
No. 8. Sambucus niger 
(young). 
absorption of the extreme red is general), and inten¬ 
sifies the absorption of the violet. After having 
carefully examined the solutions, in this and many 
other methods giving more or less negative results, 
my attention was turned to the chlorophylls of the 
various plants on which the insects were likely to 
have fed, with a view to ascertaining the absolute 
identity of the chlorophyll of the plants with the 
chlorophyll-like green substance of the cantharides. 
This was a more difficult matter than would at first 
appear, because newly gathered and young leaves, 
such as one would gather now, give a very different 
spectrum from that of old leaves, especially if these 
latter be kept long and become thoroughly dried. 
There is, for example, one notable reaction of 
young leaves which has not, so far as I know, been 
published. It is this : If an ethereal solution of the 
chlorophyll of, say, a young lilac leaf be acted upon 
