632 THE RESPIRATION AND [pt. iii 



material he showed that the egg-Breis of unfertihsed eggs respired 

 rather more strongly than the intact unfertilised eggs themselves, but 

 that the reverse relation held true of fertiUsed eggs. What was very- 

 important was the demonstration that, though there was a difference 

 of 500 to 700 per cent, between the respiratory rates of fertilised 

 and unfertihsed eggs, this difference practically disappeared in the 

 cytolysed centrifuged material, for it possessed apparently the same 

 respiratory rate, no matter whether it came from unfertilised or 

 from fertilised eggs. Sometimes there might be as much as 15 per 

 cent, in favour of the fertilised eggs, but no more. Moreover, if it 

 was true that the spermatozoon influenced the oxidative activity of 

 the egg almost entirely through its effect on the cell-boundary, it 

 should follow that the addition of spermatozoa either intact or 

 cytolysed to the egg-Breis would produce no rise in respiratory rate. 

 This was actually found. Some typical figures on which the above 

 conclusions were founded are given here. 



Respiratory rate (c.mm. oxygen used 

 in 20 min. by amount of egg cor- 

 responding to 20 mgin. nitrogen 

 at 22°; several experiments) 



Unfertilised eggs, intact ... 14 13 12 



Unfertilised eggs, destroyed ... 21 22 21 



Unfertilised eggs, destroyed ... 25 22 26 23 21 



Fertilised eggs, destroyed ... 21 23 25 22 19 



Oxygen used up in c.mm. 



Brei plus 



Brei plus sperm in 



Control sperm in distilled 



Minutes Brei alone sea water water 



20 29 27 30 



40 51 50 51 



60 67 67 71 



In some of the experiments Warburg estimated the carbon dioxide 

 production, getting respiratory quotients of 0-68 and o-8o, but he laid 

 no stress on them for various reasons connected with technique. 



Warburg used these " Granulasuspensionen " of the centrifuged 

 cytolysed eggs for the purpose of studying the effect of added iron on 

 the oxygen uptake. It may suffice to say here that he showed that the 

 addition of minimal amounts of iron salts increased greatly the uptake 

 of oxygen by the centrifuged cells. He also showed that it stimulated 

 the production of carbon dioxide by the same material, and that the 

 excess respiration brought about by the addition of iron was of the 



