The secretory ameloblast of the mini-pig foetus

Electron microscopic investigations of secretory ameloblasts from deciduous tooth germs of mini-pig foetuses and investigations of the ability of various fixatives to preserve these cells in tooth germs immersion-fixed in toto 5 min, 10 min, 15 min, 20 min and 40 min after death of the mother gave the following results:

1.	The ameloblasts exhibit ultrastructural characteristics typical of exocrine secretory cells of merocrine type.
2.	The localization of organelles is as in rodent secretory ameloblasts, but differs from the location in the human analogues.
3.	Fixation with 4% formaldehyde invariably gives unacceptable ameloblast preservation.
4.	Fixation with 2.5% glutaraldehyde gives fair preservation of the ameloblasts when the germs are fixed within 10 min of the death of the mother.
5.	Fixation with a fixative mixture 2% formaldehyde — 1.25% glutaraldehyde gives good preservation when the ameloblasts are fixed within 15 min of the death of the mother.
6.	Fixation with a fixative mixture 2% formaldehyde — 1% glutaraldehyde — 1% acrolein gives good ameloblast preservation when the germs are fixed within 15 min of the death of the mother.