624 THE RESPIRATION AND [pt. iii 



introduced by bacteria, spermatozoa, and teratological complica- 

 tions. His principal figures were as follows: 



Mgm. oxygen used per hour by 



weight of egg corresponding 



to 28 mgm. nitrogen 



Unfertilised egg 0-055 



Fertilised egg ... ... ... 0-303 



8-cell stage 0-355 



32-cell stage ... ... ... 0-576 



Warburg mentioned the fact that Loeb had found that unfertilised 

 echinoderm eggs would live well for a week in sterilised water. During 

 this period they would absorb oxygen, so evidently a definite metabolic 

 turnover was proceeding in them. Fertilisation led to a multiplication 

 of the metabolic rate by 6 or 7. Later development seemed to show 

 no change at the 8-cell stage, but some increase at the 32-cell stage. 

 Warburg also investigated the effect of hindering or stopping 

 altogether the cleavage of the eggs by placing them in hypertonic sea 

 water ( I gm.NaCl added to looc.c. sea water). The respiratory rate was 

 practically unaffected, being 0-368 mgm. oxygen per hour per 28 mgm. 

 nitrogen in the normal case and 0-347 i^igm. in the inhibited case. 

 A comparison between the rate of respiration of the egg and the 

 spermatozoon demonstrated that the former respired about 500 times 

 as much as the latter. The influence of hypertonic sea water, however, 

 was found by Warburg to be a little different in the unfertilised egg. 

 Recently Runnstrom has observed an increase of respiratory rate in 

 hypertonic solutions. Loeb had shown that hypertonic solutions 

 were active agents only if they contained dissolved oxygen, and had 

 concluded that they had an effect on the respiratory rate. In Warburg's 

 experiments this actually turned out to be the case; for example: 



Treatment for half hour Mgms. oxygen used per hour per 28 mgm. 

 gm. sodium chloride per nitrogen after the eggs had been 



100 c.c. sea water put back in ordinary water 



I 0-085 



2-3 + 1-6 c.c. jV/io soda 0-282 



4-3 +3-0 c.c. JV/io soda 0-535 



Just the same effects were observed on treatment with hypotonic 

 sea water, so it seemed as if some, at any rate, of the agents which 

 would induce artificial parthenogenesis would also induce the high 

 respiratory rate characteristic of the newly fertilised egg. As was to 

 be expected, the temperature coefficient of the respiration was found 

 to be approximately 2, for at 20° the respiratory rate of unfertilised 

 eggs was 0-059 '^g- oxygen, and at 28° it was o-i 18 mg. oxygen. 

 In his second paper, Warburg dealt principally with the effect of 



