416 Dr. C. Shearer. Heat Production and Oxidation 



passed through, the cotton plugs used to close the flasks. The air thus 

 saturated with moisture and at the same time brought to the temperature of 

 the water bath, as Hill has shown, the heat capacity of air being so low, 

 produces little or no cooling effect on the contents of the flasks. At the 

 commencement of an experiment care was taken to adjust both flasks, but 

 especially the control flask, to exactly the same temperature as the thermostat 

 water, which, as already mentioned, was kept constantly at 14"5° C. This 

 adjustment in the case of the control flask was always made to within a 

 hundredth of a degree C. with a Beckmann thermometer. This adjustment 

 was usually carried out several times in succession before an experiment was 

 actually commenced. The sperm were suspended in a small bottle in the 

 water of the thermostat, so that when finally added to the eggs in the flask 

 they were at approximately the same temperature. 



On the addition of the sperm the cotton plugs, with the thermocouple 

 junctions and air tubes, were immediately replaced in the necks of the flasks, 

 and galvanometer readings commenced. Eeadings were always taken at 

 fairly frequent intervals at the commencement of an experiment, but once 

 the experiment was under way, they were usually taken at intervals of 

 several hours. The readings obtained, in millimetres on the galvanometer 

 scale, were then plotted out on squared paper with respect to time, and a 

 curve of observed heat production obtained. As the flasks are meanwhile 

 losing heat, a correction for heat loss has to be made. The loss of one flask, 

 however, by the conditions of the experiment has been made the same as that 

 of the other, so that the rate of temperature-rise in the flask containing the 

 eggs is immediately given by the formula h (T — Ti), where k is the coefficient 

 of temperature-loss of the flask, and (T — Ti) is the difference of temperature 

 between the two flasks, as shown by galvanometer scale readings in milli- 

 metres at any instant. The total temperature-rise in the flask is obtained 

 by integrating &(T — T x ) with respect to time, and this value is accurately 

 given by measuring the area of the curve given by the galvanometer scale 

 readings plotted against time. The total heat produced is equal to the 

 capacity of the flasks and fluid multiplied by the final temperature difference 

 between the flasks plus this value of k (times area of curve), where this last 

 expression is equivalent to k [value of the middle ordinate of (T — Ti)]. 



In the following sections of the paper, a few only of the many experiments 

 carried out have been described. In many instances the eggs or sperm, for 

 one reason or another, were unsatisfactory and the experiment failed to give 

 a result. In other experiments, while the eggs and sperm were perfectly ripe 

 and the eggs gave a very high percentage of fertilisation, they failed to 

 fertilise in the manometers to the same extent as they did in the flasks, 



