On the relation of the body length to the body weight and to the weight of the brain and of the spinal cord in the albino rat (Mus norvegicus var. albinus) / by Henry H. Donaldson.

  • Donaldson, Henry Herbert, 1857-1938.
Date:
1909
Catalogue details

Licence: In copyright

Credit: On the relation of the body length to the body weight and to the weight of the brain and of the spinal cord in the albino rat (Mus norvegicus var. albinus) / by Henry H. Donaldson. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    differences in this relation according to sex, as well as to make com- parisons with other forms. It also permits the determination of the influence of dwarfing and other modifying conditions on the weight-length relation. 3. Both the weight of the brain and of the spinal cord can be related to the body length, and the measurement on body length thus made to furnish an additional datum from which the weights of the brain and of the spinal cord can be inferred. As we shall see, this datum is a much better one than body weight, especially in those cases where, for one reason or another, the animal has become emaciated. 4. If we consider the body length of the rat to correspond in a general way with the sitting height in man, we have one more means of comparing the growth changes in the two forms. In the following pages we shall discuss these points, so far as they have been worked out. For the mathematical treatment of the results 1 am indebted to my colleague, Dr. Hatai, who is pub- lishing at this same time some notes on the formulas previously used by both of us (Hatai, ’08; Donaldson, ’08), as well as giving a new and more general formula for determining the weight of the brain from the body weight (Ilatai, ’09). The technique of weighing and measuring was that described in the earlier paper (Donaldson, ’08). A number of complete rec- ords on the albino rat have been added to those on hand at that time. Moreover, for the relation of body weight to the body length alone, additional records have been obtained by weighing and meas- uring animals which had been anaesthetized lightly. It was my first intention to print the full series of individual records (233 males, 173 females) in a general table at the end of this paper. I have, however, decided not to do so for the following reasons:— First.—Printing such a general table would involve repeating a number of the records already published in a former paper (Don- aldson, ’08), and would in turn need to be again repeated in a forth- coming paper on the change in the percentage of water during the growth of the nervous system.