Just purchased some diatom strew slides from Carolina Biological Supply
http://www.carolina.com/browse/product- ... ubmit=true
They are celebrating their 90th anniversary and I realized when ordering that I have been doing busness with them for over 50 years (When I was thirteen I was buying leopard frogs from them for a science fair project on Galvanic muscle contraction).
The Diatomaceous Earth slide is absolutely spectacular - many many whole specimens. The other diatom slides have some problems:
First, they are stained so many of the chloroplasts have bizarre coloration. I may only shoot them in black and white.
Second - the mounts are very thick. With mountant and cover slip they measure .77mm, which precludes the use of my 60x objective. The best I can do is the 40x which has more working distance than the 60x.
Mike