TECHNICAL NOTES AND BIBLIOGRAPHY 263 



127. Keosian, J. Secretion in tissue cultures. III. To- 

 nicity of fluid in chick mesonephric cysts. Journal 

 of Cellular and Comparative Physiology, 12: 23. 



1938. 



128. Macallum, a. B. The paleochemistry of the body 

 fluids and tissues. Physiological Review, 6: 316. 

 1926. 



129. Nash, J. The number and size of glomeruli in the 

 kidneys of fishes with observations on the morphol- 

 ogy of the renal tubules of fishes. American Journal 

 of Anatomy, 47: 425. 1931. 



130. Pitts, R. F. Urinary composition in marine fish. 

 Journal of Cellular and Comparative Physiology, 



4' 389- 1934- 



131. Smith, H. W. The excretion of phosphate in the 

 dogfish, Squalus acanthias. Journal of Cellular and 

 Comparative Physiology, 14: 95. 1939. 



Some years ago the Canadian physiologist, A. B. 

 Macallum {128}, advanced the view that the blood 

 plasma of the vertebrates and invertebrates with a closed 

 circulatory system is, in its inorganic salts, a reproduc- 

 tion of the sea water of the geological period in which 

 the representatives of such forms first made their ap- 

 pearance. This theory is clearly inappUcable to the verte- 

 brates, which were evolved not in the sea but in fresh 

 water, and it is questionable if it is applicable to any 

 invertebrates. Macallum's thesis has been cogently criti- 

 cized by W. J. Dakin {109} in an excellent paper that 

 has been generally overlooked by students of this sub- 

 ject. 



Of the extensive literature on the anatomy and physi- 

 ology of the kidney in the lower vertebrates, only the 

 most recent will be included here in order to bring this 

 literature up to date, but those cited will supply a guide 

 to earlier papers. Anatomical studies have been reported 

 by numerous investigators {37, 53, 85, 110, 111, 112, 



