ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 175 



after a dichromatic fixation with the appHcation of heat. In certain 

 species, e.g. cat, different portions of the tubule have characteristic 

 Hpoid formations which may indicate a difference in function. The 

 mitochondrial rods of the ascending limb of the medullary loop are by 

 nature strongly lipoid and are resolved into lipoid granules under 

 certain conditions. The presence, distribution, and, in some cases, 

 characteristic distribution of lipoids in kidney cells suggest that they 

 may be intimately connected with metabolic processes, besides perhaps 

 having the function of influencing the physical state of the proto- 

 plasm. J. A. T. 



Pyloric Caeca of Herring. — E. Ford {Journ. Marine Biol. Assoc, 

 1920, 12, 325-31). An examination of 475 females and 600 males 

 showed that the general variation in the number of c^eca is from 14 to 

 28, the most frequent number being 21, that there is no appreciable 

 difference between the sexes, and that although the mean of the number 

 is greater in the longer fish, the successive increases are not sufficiently 

 great to be of much significance. In another sample of 197 the 

 commonest occurring number was 22, in a general variation from 16 to 

 34 (two specimens over 30). J. A. T. 



Deg-eneration of Pancreas during Pregnancy. — M. Aron {Comptes 

 Rendus Soc. Biol., 1920, 83, 1122-5). Description of curious de- 

 generative changes in the pancreas of bats, goats and various other 

 mammals during pregnancy. There is more or less intense autolysis 

 of the pancreatic acini. It may be that some toxin from the peritoneal 

 serosa passes into the wall of the pancreas where it is in contact with 

 the peritoneum. J. A. T. 



Function of Lymphoid Tissue.— J. Jolly {Comptes Rendus Soc. 

 Biol., 1920, 83, 1209-12). It has been usual to regard lymphoid 

 tissue as the seat of the formation of blood cells. In the lymphoid tissue 

 of the spleen and the marrow red blood cells and leucocytes suffer dis- 

 integration and are replaced. The cells in lymphoid tissue have well- 

 developed nucleoplasm and little cytoplasm ; there is a reserve of 

 nucleo-proteins as well as of blood-corpuscles. J. A. T. 



Function of Embryonic Kidney. — J. Firket {Compies Ptendus Soc. 

 Biol., 1920, 83, 1230-1). In tlie embryo cat it has been possible 

 to show that as soon as the glomeruli are developed the embryonic 

 kidney is able to eliminate crystalloid salts (ammoniacal citrate of iron 

 and ferro-cyanide of sodium). J. A. T. 



Adsorption of Hydrogen Ions by Living Cells. — J. Gray {Journ. 

 Physiol. , 1920, 54, 68-78). Under normal conditions the egg of the 

 trout lives in water containing a very low concentration of electrolytes. 

 The egg itself, on the other hand, has a much higher ekctrolytic content. 

 It is shown that when the living eggs are exposed to dilute concentra- 

 tions of hydrochloric acid, the hydrogen ion is taken up, but the 

 concentration of chlorine ions in the external solution remains practicidly 

 unchanged. To replace the hydrogen ions removed from the solution, 

 a kation (possibly potassium) is given up by the Q%g9. The uptake of 



