122 EXPERIMENTS IN MOUNTING THE AMPHIPLEURA PELLUCIDA, 
swimming along with a Pinnularia in company. I secured as 
much as I could conveniently carry, and on getting back to the 
hotel I thought I was doing a good thing in getting it carefully 
dried in a stove. On sending a sample to a friend to prepare a 
few slides for me in order that I might get it tested with a standard 
specimen, he told me that the A. pellucida were in abundance, 
but the valves were so broken up from the severity of the mani- 
pulation he required to subject the material I sent, that if I gave 
im the information where to find it he would make arrangements 
to get a fresh supply and prepare some slides from the wet material. 
I immediately sketched a rough plan of the locality ; at the same 
time bound him down to keep the place a secret, as I knew if this 
place was once known to the diatom hunters, they would rush from 
all parts of Great Britain to obtain a supply, and probably in twelve 
months time no more A. pellucida would be found in that pool. 
with a standard specimen, and the opinion given was that the 
strie were more delicate and numerous than on the standard 
specimen. 
During the fourteen months I was away from this Colony, every 
lake, stream, or waterhole which I came across was subjected to a 
micro-examination for diatoms, and it was only in Scotland and 
America that I found the A. pellucida. It is simply that I have had 
an abundant supply of this diatom that I have been able to carry on 
and verify the experiments which I am about to relate to you this 
evening. 
In the early part of 1881 I mounted three slides of the A. 
pellucida in phesphorus. Originally the slides were sent out to 
this Colony as test slides, mounted by Wheeler. On examination 
the diatoms were found to be fixed on the slide instead of the cover- 
glass, consequently perfectly useless for hom. lenses. I too 
A. pellucida in this medium, as up to that date I considered my 
phosphorus mounts second to none in the world. And now you 
have the secret why I have been experimenting ever since. . 
Chase states the difficulty he and Prof. Smith have to contend with 
1s in the ringing, as his medium attacks the cement and his specl- — 
mens become spoi You will see that, with the exception of 
