56 



T ranxactioiis. 



hatching results. Reference to the paper akeady referred to will show 

 that these conditions were entirely different from those adopted last year, 

 when 7,500 eggs were placed in each of the five boxes of one of these sets, 

 and the eggs were simply laid on the bottom of the box. On this occasion 

 the 2,000 eggs w^ere placed on a gauze tray at least an inch from the bottom, 

 .and the water circulated through the tray, flowing from the bottom upwards. 

 It is no doubt entirely due to these better conditions that the death-rates 

 to be given are so low compared with last year's, when the conditions were 

 previously known to be such as would produce great mortality, both in the 

 ■egg and yolk-sac stage. 



An examination of the radio-activity of the water of the top boxes in 

 each set revealed the fact that whereas the activity of one set was 126, the 

 same as last year, and expressed in the same units, the activity of the top 

 box of the other set was only 78. As this difference existed between the 

 radio-activity of the two boxes, a very careful examination of the gas- 

 content of the two boxes was made. The results appended are a mean of 

 five determinations of each box, and in no single case did the result differ 

 appreciably from the mean. 



