SECTIONAL TRANSACTIONS.—I. 533 
calcium balance, together with histological sections of bone and radiograms 
taken by controlled methods. In rickets and osteomalacia, vitamin D 
restores the blood chemistry and radiogram picture to normal. Investi- 
gations suggest that the theory of halisteresis is erroneous, and that the 
action of vitamin D is to calcify osteoid seams. 
Clinical, biochemical, radiographic and histological evidence exists that 
two hormones influence the metabolism of bone. The parathyroid hormone 
raises the serum calcium, depresses the plasma phosphorus, and causes 
excessive excretion of calcium in the urine. The thyroid hormone raises 
the excretion of calcium in both urine and faces, but there is no increase 
in the serum calcium. Calcium is removed from the skeleton both in 
hyperparathyroidism and in hyperthyroidism, and in both the mechanism 
of removal is a lacunar resorption by osteoclasts. 
PRESIDENTIAL ADDRESS by Prof. E. D. ADRIAN, F.R.S., on The activity 
of nerve cells (12.0). (See p. 163.) 
AFTERNOON. 
Col. C. J. Bono, C.M.G.—Some recent observations on certain phases of 
leucocytic and erythrocytic activity (illustrated with the projection 
microscope) (2.0). 
(1) Incubated leucocyte films showing— 
(a) active, (b) resting, (c) reactivated cells. 
(2) Endothelial cells. Ditto. 
(a) resting cells ; (6) active cells ; (c) phagocytosed red cells. 
(3) Phagocytosis of pigment particles in active, resting and reactivated 
cells. 
(4) Leucocytes and dendrites (3). 
(5) Living pus cells. 
(a) active, (5) resting. 
(6) Washed red cells, showing passage from disc, through prickled, to 
the spheroidal shape. 
(7) foot to disc form by addition of blood serum or soap (sodium 
oleate). 
(8) Auto (pseudo) compared with group agglutination. 
(9) Effect of reagents on intracellular hemoglobin. 
(10) Avian, amphibian and fishes’ red cells. 
Dr. F. J. W. Roucuton.—Carbon dioxide transport in blood : recent 
developments (2.45). 
This paper surveys the changes in outlook which have occurred during 
the past three years due to— 
(a) The isolation from red blood corpuscles of an enzyme, carbonic 
anhydrase, which accelerates the formation of carbon dioxide from 
carbonic acid, and vice versa. 
(6) The evidence that some carbon dioxide may be carried in direct 
combination with the blood proteins, probably as protein carbamate. 
Dr. THomas BeprorD and Mr. A. F. Durron.—WNose-opening rays (3.15). 
Leonard Hill’s theory that there are ‘ nose-closing’ rays and ‘ nose- 
opening ’ rays appeared to be of paramount importance in the study of the 
