EXPERIMENTAL STUDY OF THE OYSTER GILL 35 



heart action, may abnost be said to hibernate." An indirect evidence of hibernation 

 was suppHed by Gorham (1912), Pease (1912), and Gagje and Gorham (1925), who 

 based their conclusions on the study of seasonal fluctuations in B. coli content in 

 oysters taken from polluted bottoms. Physiological study of the problem was impos- 

 sible, however, as no method was offered whereby the cihary activity of the gills could 

 be measured. The present paper, based on a quantitative study of the activity of 

 the gills, supports fully the ideas advanced by Gorham, Pease, and Gage. How- 

 ever, the facts described in it contradict the conclusions reached by Nelson (1923) 

 that "the rate of filtration of water during any given period of time, as deduced 

 from the rapidity and extent of ejections of accumulated sediment from the mantle cav- 

 ity, may vary widely, independently of the temperature and turbidity of the water." 

 No attempts were made in the present investigation to study the effect of turbidity 

 of the water, but the role of temperature in the cihary activity of the gill epithe- 

 lium was estabUshed and is shown in Figures 5, 6, 7, and 8. 



Knowledge of the effect of temperature on the activity of the gill epithehum 

 of the oyster is essential in many practical problems of the oyster industry. From 

 the sanitary point of view, the fact that at a temperature of 5° C. and below the oyster 

 does not take in any water and ceases feeding, suppHes an additional safeguard, which 

 can be appHed in the sanitary control of oyster bottoms. In the purification of oysters 

 by chlorination an understanding of the role temperature plays in the functioning of 

 the gills is of great importance. The method of chlorination introduced in 1914 by 

 Johnstone (1915) is based on self-puriiication of oysters, which are allowed to filter 

 sterile sea water; and knowledge of the rate of filtration at a given temperature is 

 necessary for an intelhgent operation of the chlorination plant. 



It is a common practice in certain areas to take oysters from sUghtly polluted 

 beds and to relay them on clean, unpolluted bottoms. Sometimes this operation is 

 carried out during the cold season when the temperature is below 5° and the oysters 

 have no possible chance to cleanse themselves. It is obvious that the determination 

 of the minimum period of time oysters should be left on new bottoms should be based 

 on the rate of filtration of water at a given temperature. •! 



For a study of the physiology of the oyster a knowledge of the rate of filtra- 

 tion of water is of fundamental importance. Fattening, growth, and ripening of the 

 gonads are probably directly dependent on the amount of food consumed. At present 

 we know almost nothing regarding these activities of the oyster, and the author is 

 convinced that the present investigation may facihtate, to a certain extent, the attack 

 of other problems that are of great importance for an understanding of the factors 

 responsible for the fluctuations in the oyster crops in our waters. 



RESUME 



1. Two methods are described whereby the rate of flow of water produced by 

 the cihary epithehum and the pressure inside the gill cavity of the oyster can be 

 measured accurately. 



2. The mechanical work performed by the oyster gills in producing a current 

 of water can be expressed by the following formula: W^2TrlnS^, where TF = work 

 in ergs per second; 1-= length in centimeters of the glass tube through which the 



