Hi Sharon,
	After struggling with the Bouin's fixation procedure for quite awhile, I think we've found the happy medium as far as good testes fixation for rodents and large animals. Bouin's, unfortunately is the fixative of choice for testes because of it's excellent cytological detail. For good fixation in Bouin's It is essential to first, do not over fix the specimens and second, remove as much picric acid as possible after fixation. The timing is different for mice, rats and large animals.
Large Animal Testes
		Prior to fixation in Bouin's solution, carefully trim each testis with a razor, PathcoŽ or any sharp
 blade that will allow you to gently, without squeezing and with one smooth motion draw the
 blade across and completely through the testes. Trim approximately 1/3 - 1/4 off or into each
 testis. Each transverse cut will be somewhat off center of the organ [or you can remove 
˝ - 1cm from each pole].
		Place the testes in an appropriately labeled  mega-cassette or bag in a container. 
	Fix in Bouin's solution for a minimum of 20 hours and not more than 24 hours.
			After fixation, pour off the fixative into a suitable safety disposal container and
		                                 proceed with the following process.             
	Wash the testes in running water, a minimum of 2 hours but no longer than 4 hours.
	Place the testes in a solution of equal parts [50:50]
			*[10% phosphate buffered formalin : absolute ethanol for a minimum of 24 hours]. 
  	*70% ethanol, a minimum of 20 hours.                                                                                                                                            
                *70% ethanol, a minimum of 16 hours.
			Testes can be either trimmed and/or stored in 70% alcohol. Start processing in 70% alcohol.
			*This step may be significantly aided with the use of a magnetic stirrer. 
Note:	The maximum amount of specimens allowed per bucket after the running water rinse is 20-25 specimens/approximately 3500 mL of solution in a 4000 mL beaker.
		
Do not place the tissue on the processor in formalin. The processor must be started in 70% ethanol. The remnants must be stored in 70% ethanol.
		
If this doesn't read or print correctly send me your fax# or I'll resend.
Dave

>>> Sharon E Willman <sharon.willman@bms.com> 07/24 1:43 PM >>>
I am needing information on large animal testes, particular
canine testes, type of fixation and do you have a special
technique for taking sections without damaging the testes.

We currently fix them at necropsy in 10% formalin, making cuts at

both poles poles.
We are having damage to the testes, showing up microscopically,
and also there does not seem to be proper infiltration of
formalin in the testes.  They are pink in the center 2-3 days
after being put in the fixative.

Any information you can give me would be most appreciated.

Thanks,

Sharon