PROCEEDINGS 



OF 



THE ROYAL SOCIETY. 



Series B. Vol. 88. No. B 606. 



BIOLOGICAL SCIENCES. 



CONTENTS. 



Page 



Investigations on Protozoa in Relation to the Factor Limiting Bacterial 

 Activity in Soil. By T. GOODEY, M.Sc, Protozoologist, Research 

 Laboratory in Agricultural Zoology, University of Birmingham . . 437 



On the Mesodermic Origin and the Fate of the So-called Mesectoderm in 



Petromyzon. By S. HATTA (Sapporo, Japan) ..... 457 



On the Variation in the Growth of Mammalian Tissue in Vitro according to 

 the Age of the Animal. By ALBERT J. WALTON, M.S., F.R.C.S., M.B., 

 L.R.C.P., B.Sc (Plate 15) 47<* 



Obituary Notices of Fellows Deceased : — Walter Holbrook Gaskell ; Joseph 



Reynolds Green . . . . . . . . xxvii — xxxviii 



printed for THE ROYAL SOCIETY and sold by 



HARRISON & SONS, 45, ST. MARTIN'S LANE, LONDON, W.C. 

 Price Two Shillings and Sixpence. 



No. B 606. 



April 1, 1915. 



