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Proceedings of the Poyal Society 
I obtained by digesting tbe organ itself with boiling water a 
filtrate containing leucin and tyrosin, The ferment has no action 
on cellulose. From these investigations I am led to the conclusion 
that the so-called “ liver ” of Sepia officinalis (the cuttle-fish) is not 
a true liver, — but is a pancreas , — for the juices of the organ in 
question are purely digestive in function, digesting starch, oil, and 
similiar bodies ; and transforming fibrin into leucin and tyrosin. 
Then again albumin is found in its secretion, which is characteristic 
of the pancreatic fluid of the higher animals, — no albumin being 
found in the liver, for albuminoids are decomposed by that organ. 
This organ of the Sepia digests oil-globules, and the secretions 
from a true liver are incapable of digesting fats without the pan- 
creatic fluid. 
No glycocholic and taurochloic acids nor glycogen were obtained 
from the organ, nor could the slightest trace of them be detected in 
the organ or its secretion. The above investigations prove that this 
so-called “ liver ” of the Cephalopod is a true pancreas or digestive 
organ. 
I may mention here that the leucin and tyrosin from the organ I 
have mounted as microscopic slides. 
Monday, Qth April 1885. 
JOHN MURRAY, Esq., Ph.D., Vice-President, 
in the Chair. 
The following Communications were read : — - 
1. Chromomictors. By Mr John Aitken. 
The instruments which we have called chromomictors, have been 
designed for the purpose of mixing lights of different colours for 
experiments in physiological optics. There are already a consider- 
able number of instruments for this purpose, but none of them are 
perfectly satisfactory. We shall here describe one or two new forms 
of apparatus which have been recently experimented with, and 
though they may not be suitable for many colour experiments, yet 
they seem to possess some advantages over several of the instruments 
