666 THE RESPIRATION AND [pt. iii 



veloped normally, after which a titration at varying intervals was 

 all that was necessary to give him his curve. In Fig. 1 24 are shown 

 some curves constructed from the data which he obtained. They are 

 neither smooth nor regular, but Bataillon, it must be remembered, 

 was engaged in pioneer work. The continuous line is the curve 

 for the minnow. The curves show, as he himself pointed out, 

 (a) a rise during segmentation followed by {b) an accentuated fall 

 during the extension of the blastoderm over the yolk-sac, after which 

 the curve climbs again {c) to a peak at the end of the covering of 

 the yolk by the blastoderm. Then there is a period {d) of lowering 

 at the time of the occlusion of the yolk-plug, followed by {e) a 

 slow rise till the beginning of active movement. It is difficult to 

 know what emphasis to lay upon these results, for the description 

 of the technique by which they were obtained is so short that no 

 adequate idea can be had of it, and it presents, moreover, suspicious 

 features. 



It may be remarked in passing that the curves given by Bataillon 

 are increment curves, and thus show up minor variations in the more 

 or less regular curve relating time to oxygen uptake. 



Scott & Kellicott in 19 16 made an extended study of the respiratory 

 exchange of the embryos of another minnow, Fundulus heteroclitus. 

 Unfortunately, this was never published, and all that we have is an 

 abstract which gives nothing but the main points, and those almost 

 too briefly to be of service. According to Scott & Kellicott, in the 

 early cleavage stages 1000 eggs use o-i c.c. of oxygen per hour. 

 The appearance of the circulation of the blood produces a marked 

 rise, after which another steady level supervenes, so that at hatching 

 they are using 0-7 c.c. of oxygen per hour, having consumed through- 

 out the entire period from fertilisation to hatching about 80 c.c. Six 

 days after hatching they use 1-75 c.c. per hour. From fertilisation 

 to hatching 38 per cent, of the egg-weight is lost, presumably by 

 combustion. One thousand eggs in early cleavage stages were found 

 by Scott & Kellicott to consist of 0-12 gm. of protoplasm and 2-65 gm. 

 of yolk, but 6 days after hatching they weighed i-8 gm.; 0-12 gm. 

 of protoplasm used o- 1 c.c. of oxygen per hour, so that the metabolic 

 rate for the early cleavage stages was 8-34 c.c. oxygen per hour per 

 100 gm., and from the figures given for 6 days after hatching it was 

 9-74 c.c. 



Hyman also worked on Fundulus eggs with the Winkler method. 



