img_oph_high = new Image(199,125);
img_oph_high.src = "http://www.biologicaltestcenter.com/public/themes/btc/images/ophthalmology_high.gif";  
img_oph_norm = new Image(199,125);
img_oph_norm.src = "http://www.biologicaltestcenter.com/public/themes/btc/images/ophthalmology.gif";  

img_pharm_high = new Image(199,125);
img_pharm_high.src = "http://www.biologicaltestcenter.com/public/themes/btc/images/pharmacokinetics_high.gif";  
img_pharm_norm = new Image(199,125);
img_pharm_norm.src = "http://www.biologicaltestcenter.com/public/themes/btc/images/pharmacokinetics.gif";  

img_sur_high = new Image(199,125);
img_sur_high.src = "http://www.biologicaltestcenter.com/public/themes/btc/images/surgery_high.gif";  
img_sur_norm = new Image(199,125);
img_sur_norm.src = "http://www.biologicaltestcenter.com/public/themes/btc/images/surgery.gif";  

img_tox_high = new Image(199,125);
img_tox_high.src = "http://www.biologicaltestcenter.com/public/themes/btc/images/toxicology_high.gif";  
img_tox_norm = new Image(199,125);
img_tox_norm.src = "http://www.biologicaltestcenter.com/public/themes/btc/images/toxicology.gif";  

img_sci_high = new Image(199,125);
img_sci_high.src = "http://www.biologicaltestcenter.com/public/themes/btc/images/biocomp_high.gif";  
img_sci_norm = new Image(199,125);
img_sci_norm.src = "http://www.biologicaltestcenter.com/public/themes/btc/images/biocomp.gif";  

function mouse_on(img_name)
 {
    img_high=eval(img_name + "_high.src");
    document[img_name].src= img_high;
 }

function mouse_off(img_name)
 {
    img_norm=eval(img_name + "_norm.src");
    document[img_name].src= img_norm;
 }