504 H. M. CARLETON 



of fixatives. For in this connexion it is a matter of common 

 knowledge that fixed specimens of kidney frequently show 

 swelling or (more usually) shrinkage of the renal epithelium. 



The frogs were killed by pithing, the cats by a blow on the 

 head. The tissues were fixed immediately after death. 



Amphibian (Frog) Tissues. — The concentration of the 

 normal (isotonic) saline was 0-6 per cent. Two frogs were 

 used, i. e. the experiments were once repeated so as to observe 

 whether the effects were constant. 



(1) 6 per cent. Mercuric Chloride in 0-6 per 

 cent. NaCl. — The preservation of both liver and intestine 

 is normal. There is no evidence of either shrinkage or swelling 

 of the cells. The shape of the red blood-corpuscles is normal. 



(2) 6 per cent. Mercuric Chloride in Distilled 

 Water. — Tissues fixed in this solution are indistinguishable 

 from those fixed in no. 1. 



(3) 5 per cent. Formol in 0-6 per cent. NaCl. — 

 The fixation is normal and comparable to that obtained with 

 mercuric chloride dissolved in the corresponding grade of 

 saline (no. 1). 



(4) 5 per cent. Formol in Distilled Water. — 

 Liver. — The cells are normal in size and shape. Their cytoplasm 

 is vacuolated, and the whole appearance suggestive of some 

 change — probably of the nature of a partial solution of the 

 cell-contents — brought about by fixation. There is no distor- 

 tion of the red blood-corpuscles in the sinusoids. Intestine. — 

 In some specimens the epithelium is normally preserved, in 

 others the columnar epithelial cells are vacuolated and some- 

 what swollen. The muscular coats of the intestine are well 

 preserved. 



Mammalian (Cat) Tissues. — The concentration of the normal 

 saline employed in this series was 0-9 per cent. The observa- 

 tions were once repeated, as for the frog series. 



(1) 6 per cent. Mercuric Chloride in 0-9 per cent. 

 NaCl. — Liver. — The fixation is normal. The red blood- 

 corpuscles are not distorted. Duodenum. — Both intestinal 

 epithelium and muscle are well fixed. Kidney. — The fixation 



