Abstract
As far as we are aware, no reports have been made of calcium in the blood of fish. In the course of a study of various physiologic phenomena in the cod, a marked difference was found in the level of calcium in the blood of the male and the female. The percentage in the former was found to be approximately 9 to 12.5 mg., the cause of the variability not being ascertained. In the female a percentage as high as 29 was not uncommon, the lowest figure being 12.7 mg. These variations were due clearly to the generative state of the fish. When the roe was large and mature, the serum calcium percentage was high, whereas when the roe was hard, or after the fish was spent, the percentages were markedly lower. A similar relationship between spawning season and calcium level of the serum was found to exist in the puffer fish. Calcium in the female was found as high as 26 mg. %, whereas in the male it was about 12 mg. %. This phenomenon is not, however, common to all fish. For example, in the dog fish, a viviparous species, the calcium level was high in both male and female.
The inorganic phosphate was far more constant than the calcium. Generally it ranged between 9 and 12 mg. %, the former amount having been obtained in a female cod which had 17.8 mg. % of calcium in the blood. The highest figure was 14.7 in a female with 13.3 mg. % of calcium. Nor does it vary with the spawning season, a fact which is emphasized' by an instance in which a female with a calcium percentage of 29 mg. in the blood had a percentage of inorganic phosphorus of only 10.9 mg.
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