674 



THE RESPIRATION AND 



[PT. Ill 



just as much associated with high respiratory rate as mitotic activity. 

 The question is in a confused and unsatisfactory state, and further 

 researches with more accurate methods are greatly to be desired. 



Another pioneer worker on the respiration of the amphibian em- 

 bryo was Godlevski, who published his work in 1900 in connection 

 with the susceptibility of frog's eggs to oxygen want. His technique 

 was rather better than Bataillon's. The data he obtained are shown 

 in Fig. 128, and consist of two smoothly ascending lines composed 

 of rather scattered points. 



Nothing further was done on amphibian embryo respiration till 

 1915, when Bialascewicz & Bledovski attacked the question, using 

 the Winterstein micro-respirometer, a great advance on the technique 

 of the earlier workers. The 

 eggs of Rana temporaria 2.0 

 were used. Bialascewicz 

 & Bledovski found that, 1.5 

 during the first few hours 

 after laying, unfertilised 1.0 

 eggs hberated a "neutral 

 gas " which, as far as could 0-5 

 be ascertained, was a mix- 

 ture of oxygen and nitro- 

 gen. This doubtless arose 

 from the difference in en- 

 vironment as regards gases 

 between the ovary in the female body and the water outside. One 

 thousand eggs gave rise in this way to a positive pressure of I2'i mm. 

 16 minutes after laying, and 1-15 mm. 47 minutes after laying, but 

 thenceforward the pressure was constantly a slightly negative quantity. 

 In order to avoid technical errors which arose naturally from this 

 fact, Bialascewicz & Bledovski compensated the gaseous exchange 

 of one lot of eggs in one vessel by having an identical quantity of 

 eggs from the same female in the other vessel. Another phenomenon 

 seen in the unfertilised eggs was a notable production of carbon 

 dioxide immediately upon laying. Eggs taken from the lower part 

 of the oviduct and brought straight into the micro-respirometer 

 eliminated large amounts of carbon dioxide, presumably because 

 the tissues of the frog with which the eggs had previously been in 

 gaseous equilibrium were saturated with carbon dioxide. This carbon 



Days-^ 



Fig. 128. 



