Fig. 2. Photomicrographs of frozen sections of the thyroid gland stained with Haematoxylin-Eosin from a control animal (a) and animals exposed to 50 Hz EMF (b,c). Note the difference in follicle size in a compared to b and c. Occasional follicles with a squamous cell lining, probably due to a low activity state can be seen in a-c. There is a prominent increase in connective tissue content in b and c compared to a. All photomicrographs are of the same magnification. Scale bar, 50 µm.