204 
croscope, and, at the suitable time, the solution of Canada balsam 
was added, and the covering-glass applied. There were two great 
disadvantages in connection with specimens prepared in both 
these ways : one was that the section itself was more or less ob- 
scured by minute granules of balsam, which had been precipitated 
out of its solution in a molecular condition by contact with the 
specimen; and the other, that sections so prepared did not 
retain their characteristic appearances more than about six weeks 
or two months ; after that time they began to grow uniformly 
transparent, and were no longer of any use. The first disadvan- 
tage was obviated by using the solution of Canada balsam in ben- 
zole, instead of the balsam in chloroform, w 7 hich gives a prepara- 
tion similar in all other respects, but free from the defacing 
granules of molecularly precipitated balsam. The last disadvan- 
tage, however, in spite of all attempts, still remains ; the specimens 
so prepared have ouly a temporary value, and will fade after from 
six weeks to two months. But the operator must acquire a cer- 
tain amount of experience for himself before he will be able to use 
this method with success ; and unless his reagents be all perfectly 
pure and fresh, he will almost surely fail to secure satisfactory 
results. 
He also recommended for rapid tinting bichloride of palladium. 
Another method of double tinting was to place the section, but 
without chromic acid, in a solution of nitrate of silver (1 : 600) for 
five or ten minutes ; taken from this, washed in pure water for a 
minute, and thence transferred to the acidulated gold solution as 
before. After the reduction of the gold by formic acid, the speci- 
men may be mounted in the solution of Canada balsam in benzole, 
and then exposed to light, in order to bring about the complete 
reduction of the silver. When this has been done it will be found, 
on microscopical examination, that the epithelial elements are for 
the most part stained of a brownish-black colour by the reduced 
silver, whilst the intervening fibrous tissue elements and the walls 
of the vessel are stained purple by the reduced gold. The two 
kinds of tissue elements seem to exercise a sort of elective affinity 
for the different metals. 
At the conclusion of a short discussion on this paper Dr. Lan- 
kester requested information from the President as to the most 
convenient method of bringing before the Society the question of 
the publication of the transactions of the Society in connection with 
the new journal. He said he thought the subject was one that 
affected the dignity and usefulness of the Society, and he con- 
sidered that the change which had been lately made ought to have 
been done by a vote of the Society, and not in an unauthorised 
way by the Council. 
The President stated that the Council had power to act as they 
had done, and that the present was not the time to discuss the 
question alluded to by Dr. Laukester. 
After consultation with the Secretaries, Dr. Lankester gave 
notice that at the next Annual Meeting he should move that the 
