A series of determinations of inorganic phosphorus, calcium, cholesterol, and lecithin were made on a group of 10 animals living in the laboratory from Oct. 27, 1927, to May 17, 1928. A marked difference in both the trend and absolute values was noted in animals living in the laboratory when compared with the values obtained for animals living out-of-doors. With animals living in the open, the trend of variation for calcium was found to be the same. However, animals living in the laboratory maintained a higher level over the same period of time. The inorganic phosphorus and lecithin both showed a marked decrease and both maintained a lower level than was found in animals just received from the dealer. The cholesterol content of whole blood exhibited a similar trend in both groups of animals. However, it was found that animals living in the laboratory maintained a lower level than animals living out-of-doors.
The mean value for calcium was found to be 15.7 ±0.05, for inorganic phosphorus 4.65 ±0.05 mg. per 100 cc. of blood serum, and for cholesterol 58.2 ±0.39 and lecithin 118.4 ±1.13 mg. per 100 cc. of whole blood.
The coefficients of correlation having the highest degree of mathematical significance were obtained from the mean values for individual animals.