The quality has become variable!
Recently, the batches we received were very dark in colour - but 
one is reluctant to complain as for a while it looked likely that 
Canada balsam would leave the market!
My most recent samples seem to me to be too "dilute".  I 
wondered if the manufacturer was making their stock of balsom go 
further.
One good reason for using Canada balsam is WE Know it works 
and, even more importantly, we KNOW it lasts forever!!! Well, 
perhaps!  I have seen many slides prepared in the twenties which 
have shown NO evidence of "drying back" fading, cloudiness or 
crystalisation.
The only drawback is there may be some fading (worse if the slides 
have not been protected from light).  But it is easy to dissolve the 
balsam with xylene and remove the coverslip to restain and 
remount - in BALSAM!!
You never know what your sections may look like when you revisit 
them before your retirement at 90!
Russ Allison, 
Dental School
Cardiff
Wales