Modification of tissue oxidations in vitro

The purpose of this investigation was to determine the influence of certain substances upon oxidations by tissues in vitro, with a view of casting some light on the relation between such substances and tissue respiration after the administration of these substances to animals. The general method of investigation was similar to that practiced by Yeo. 2 Tissues and solutions of oxyhemoglobin of amphibians, reptiles, birds and mammals were employed. The tissues were placed in freshly prepared oxyhemoglobin solution made from fresh blood obtained from the same animal. The mixtures were made in test-tubes and for the most part air was not entirely excluded. The darkening of the hemoglobin solution as observed directly and the appearance of reduced hemoglobin as shown spectroscopically were taken as indicating the amount of reduction.

Preliminary experiments with mammalian tissues gave a value for different tissues somewhat different from that obtained by Bert, 3 who employed a different method. Also the results showed that tissues of warm blooded animals reduce such oxyhemoglobin solutions more actively than those of cold blooded animals; this observation agrees with the results of Battelli and Stern. 4 For the later experiments muscle and liver were more extensively employed, because of their activity and their relative bulk. The tissues were prepared by cutting into gram cubes, or chopping finely, or crushing in a mortar. Both fresh and boiled extracts made from crushed tissues were studied.