BLOOD PRESSURE AND PLASMA PROTEIN DETERMINATIONS IN THE SAME FROG

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Abstract
A new method for obtaining values of blood pres-sure in the intact frog is described. The findings obtained by this method are thought to be within the limits of error since they have been confirmed by blood pressure tracings produced with calibrated Huerthle and Harvard membrane manometers. Normal blood pressure in frogs shows an average blood pressure for Rana pipiens equal to 30.5/21.1 mm. Hg, and for Rana catesbiana, 32/21.2 mm. Hg. Blood pressure values in frogs show rather marked variations as a result of struggling and excitement, as is the case in mammals and man. Plasma protein percentages obtained by precipitation with trichloracetic acid show for R. pipiens an average of 2.71 and for R. catesbiana an average of 3.83. Plasma proteins and blood pressures in frogg tend to show some variations, but the variations in a given frog seem to affect both values in the same direction. Fluid drawn into the blood in frogs after hemorrhage appears to be protein-free as in mammals. The findings of Hayman (1927) for general systolic blood pressures in frogs have been confirmed. The averages given here are higher than those of Hayman, however. This, in all probability, is due to the fact that the frogs used by Hayman were anesthetized, or pithed, and prepared surgically for the observations. Such procedures tend to reduce the general blood pressure. There is sufficient diastolic blood pressure in the frog to over-balance the osmotic pressure of the proteins. Using Hayman''s figure to determine diastolic glomerular capillary pressure, there is again sufficient blood pressure to over-balance the osmotic pressure of the proteins.

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