Allometric study of the lachrymal and Harderian glands of the rat during postnatal life.

The authors performed an allometric study of the growth of the rat's lachrymal and Harderian glands, during postnatal life. From the analysis of the results, they could conclude: (1) the growth of these glands in relation to body weight, during postnatal life, could be considered similar, following the allometric law; (2) the differential growth of the glands occurred in two stages: from birth until the 15th day and from the 15th day until the final period of life studied; (3) the two stages of development were separated by a critical period, during which an abrupt modification of the allometric coefficient occurred; (4) during the first days of postnatal life, the development of the Harderian gland was characterized by a high rate of growth and, just after eyelid disjunction and during rest of postnatal life, by a rate of allometric of growth less than 1. It is interesting to observe that the lachrymal and Harderian glands' critical period of development on the 15th day of postnatal life coincides with the time at which the eyelids of the animal open.