Journal of Applied Microscopy. 475 



ANIMAL BIOLOGY. 



Agnes M. Claypole. 



Separates of papers and books on animal biology should be sent for review to 



Agnes M. Claypole, Sage College, 



Ithaca, N. Y. 



CURRENT LITERATURE. 

 Qorham, F. P. Some Physiological Effects of This paper embodies the results of 

 Ssoc.'3r"t°56,7pl .i,T- ""'■ some experiments made upon salt water 



fish kept in aquaria, to find the cause 

 of a gas-forming disease which produces bubbles of gas in different parts of the 

 body, sometimes filling the connective tissue of the orbits, and forcing the eyes 

 from their sockets. The experiments also throw some light on the function of 

 the air-bladder. Contrary to expectation, the disease was found not to be caused 

 by bacteria, but to be due to change of pressure. 



Normal fish, in an aquarium from which the pressure of air had been 

 removed, showed all the evidences of the disease in from a few minutes to a few 

 hours, while control specimens would remain free from the disease for several 

 days. Fish already affected were cured by being placed under a pressure of 

 twenty feet of water. Evidently, when a fish is under less than the customary 

 pressure, the gas dissolved in the blood becomes free, gas in the air-bladder and 

 tissues expands and seeks an outlet, and in this way the bubbles under the skin 

 are formed. This explanation agrees with observations made on the effects of 

 bringing deep-sea fish to the surface. The theory that the air-bladder enables 

 the fish to rise or fall in the water by changing its specific gravity is no longer 

 tenable. The gas expands, or condenses, as the fish comes to the surface, or 

 sinks to a lower level, tending to carry it still farther up or down. Apparently 

 the function of the air-bladder is to keep the fish at the same general level, 

 although it can accommodate itself to slight changes by secretion, or absorption 

 of gas by the walls of the bladder. The gases of the air-bladder are oxygen, 

 nitrogen, and carbon dioxide. If gas is liberated within the cells, as appears 

 probable, the process would be comparable with the liberation of oxygen from 

 green plants, and the fixation of nitrogen by the symbiotic bacteria of the 

 Leguminosae. The subject offers interesting questions for investigation. 



E. M. Brace. 



Observations were made upon the 



Friedmann, Franz. Ueber die Pigmentbil- formation of pigment in Vanessa urti- 

 dung in den Schmetterlingsfliigeln. Archiv . . ^ r • i j 



f. Mikr. Anat. 54:88-95, i pi., 1899. cae, begmning four days after it had 



passed into the pupa stage. Speci- 

 mens were fixed in Hermann's fluid — 15 pts. one per cent, platinum chloride, 4 

 pts. two per cent, osmic acid, 1 pt. acetic acid — in which they were left forty-eight 

 hours. The osmic acid produced a blackening of fat bodies, which are packed 

 into the leucocytes found between the lamellae of the wings, in the scale mother- 

 cells, and along the edge of the epithelium. 



These bodies are the early form of the pigment. During the development 



