An interpretation of some differences in the percentage of water found in the central nervous system of the albino rat and due to conditions other than age / Henry H. Donaldson.

  • Donaldson, Henry Herbert, 1857-1938.
Date:
1911
Catalogue details

Licence: In copyright

Credit: An interpretation of some differences in the percentage of water found in the central nervous system of the albino rat and due to conditions other than age / 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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    TABLE 3 Percentage of water in the brain and spinal cord of spayed as compared with control rats. Eleven spayed—ten controls LITTER AGE IN DAYS PERCENTAGE OF WATER IN BRAIN PERCENTAGE OF WATER IN SPINAL CORD Spayed Control Spayed Control 7 139 78.940 78.773 72.396 72.217 5 259 78.083 78.168 71.489 71.487 4 291 78.114 78.102 70.286 70.544 3 427 77.382 77.396* 69.258 69.533* Average 78.129 78.110 70.857 70.945 * The control in the third litter was killed at 384 days of age, while the spayed were killed at 427 days. The percentage of water in the control brain at 384 days was 77.482. I have calculated, however, that between that age and 427 days, the brain was los- ing water at the rate of .002 per cent per diem. The correction for the intervening 43 days was therefore made and the value, 77.396, given in the table, was that found. Similarly, I calculated that during the 43 days in question the spinal cord was losing water at the rate of .0065 per cent per diem, and accordingly the observed percentage, 69.813 was corrected to 69.533, the figure given in the table. seems the probable reason for the similarity of the percentage of water in the two groups. The foregoing series of five investigations constitute group (A). Further comment, however, on the findings in this group will be deferred until the investigations which form group (B) have been presented. Group (B) is represented by four investigations in which growth has been either arrested or retarded. This has been brought about (6) by underfeeding; observations by Dr. Hatai, (7) by underfeeding; observations by myself, (8) as the result of pneu- monia, (9) by castration, which, although it does not affect the body growth, does retard slightly the growth of the brain. (6) In 1904 Hatai (’04) by underfeeding was able to reduce the weight of the brain in rats of his first series so that at the end of the twenty-one days the brains of the underfed rats weighed 12.8 per cent less than those of the controls killed at the same time. By this treatment also the body weight was reduced to 44 per cent