Osmotic Activity Changes of Serum and Salt Solutions Placed in the Gall Bladder

Dreser, 1 the first to use cryoscopy on animal fluids, made the first determination of the osmotic pressure of bile. Numerous early investigators, among them Brand, 2 Strauss, 3 Bernstein, 4 Bosquet, 5 Koziezkowsky, 6 Messadaglia and Colletti 7 determined cryoscopically the osmotic pressure of animal and human bile obtained by various methods from living and dead specimens. They came to the conclusion that the osmotic pressure of bile, both bladder and hepatic, was approximately the same as the osmotic pressure of the blood of the same animal species; i.e. the depression of freezing point of the bile and blood both lay in the same range (about -,54°C to -,58°C for most species). Of the many objections to the earlier work, the varied methods of collection and the inaccuracy of the cryoscopic technic are perhaps the most significant. A difference in freezing point of .01 °C corresponds to a difference in osmotic pressure of nearly 100 mm of Hg. Ravdin, et al., 8 state that despite the wide variance of constituents, the osmotic pressures of hepatic and bladder bile, as determined by the depression of freezing point, are approximately the same; and that the total depression of freezing point may be accounted for on the basis of the osmolar concentration of base, chloride, and bicarbonate present. Yet the difference in osmotic pressure of their hepatic and bladder bile amounts to 357.2 mm of Hg. They also conclude that the osmotic pressure of hepatic and bladder bile is approximately the same as that of serum. On the basis of experiments in which they placed various bile constituents individually into a bile-free dog's gall bladder, Ravdin et al. 9 came to the conclusion that regardless of the concentration of the original solution, the total osmolar concentration of the fluid in the gall bladder after a period of time approaches that of serum.