Knife marks are sometimes caused by grit in the wax used for embedding. We 
had terrible problems when the lab was being repainted and dust got into the 
wax.
Best regrds

Louise Renton
Bone Research Unit
MRC
Johannesburg
South Africa
Tel & fax +27 11 717 2298
"Time flies like an arrow, fruit flies like a banana"





>From: Cynthia Favara 
>To: "'Martin, Ronald'" , 
>histonet@pathology.swmed.edu
>Subject: RE: paraffin and microtome blades for mouse tissue
>Date: Tue, 10 Dec 2002 11:36:16 -0500
>
>I have used numerous types of paraffin and after more years think it is a
>personal preference. Somewhat dependent on the type of tissue you are
>cutting. Harder paraffin for harder tissue. Most of my knife marks are
>caused by overly dry tissue or small bits of bone in the case of brain. I 
>am
>currently using paraffin from Shandon but have used Surgipath, paraplast 
>and
>a number of others. Biggest challenge on changing [my opinion only] is
>getting the temp of cold plate and water bath optimal.
>
>Cynthia Favara
>NIAID/NIH/RML/LPVD
>903 South 4th Street
>Hamilton, MT 59840
>406-363-9317
>
>
>
>-----Original Message-----
>From: Martin, Ronald [mailto:Ronald.Martin@umassmed.edu]
>Sent: Tuesday, December 10, 2002 9:09 AM
>To: histonet@pathology.swmed.edu
>Subject: paraffin and microtome blades for mouse tissue
>
>
>I was wondering what type of paraffin  research techs would suggest for
>mouse histo? Also, what types of blades section better with mouse tissue?
>I'm currently getting a lot of knife marks in my sections. All suggestions
>are appreciated.
>Thanks,
>Ron


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