818 BIOPHYSICAL PHENOMENA [pt. iii 



They also found that if morphine, cocaine, or potassium cyanide was 

 added to the egg-white in extremely small amounts (2-5 mgm. per 

 egg) the difference in osmotic concentration between yolk and white 

 could be much reduced, as if the membrane was no longer performing 

 its function. Similarly, if yolk was put into a parchment capsule 

 with egg-white outside, the system rapidly attained a state in which 

 there was only a difference of 0-01° between the inside and outside 

 freezing-points, instead of the 0-15° of the fresh egg. In another 

 interesting experiment the yolk of a fresh egg was placed in diluted 

 egg-white. 



The yolk and white of the egg were at the beginning of 



the experiment ... 

 The yolk was then placed in egg-white which had been 



diluted with an equal quantity of water. Result 

 After 48 hours the system was 



The yolk was then put back into natural egg-white. Result 

 After 48 hours the system was 



Thus in all the conditions the yolk maintained its hypertonicity, even 

 when it had sunk to 0-38 and, at the beginning of the second period, 

 was actually hypotonic to the natural egg-white. The "living" 

 vitelline membrane must therefore tend- to encourage the exit of 

 water from the yolk or to impede its entry, on the one hand, and 

 tend to encourage the entry of salts or to impede their exit, on the 

 other hand. 



If, then, the large difference m osmotic pressure between yolk and 

 white was a " Lebenserscheinung " some energy-expenditure on the 

 part of the egg-cell would be expected, and Straub & Hoogerduyn 

 calculated the " Konzentrationsarbeit " required, to be o-oi cal. per 

 egg per day. Now there exist in the literature one or two papers which 

 give the gas exchange and heat production of infertile eggs. A. J. M. 

 Smith found that one unfertilised egg gave off 0-2 mgm. of carbon 

 dioxide per day at 10° and Langworthy&Barott found that unfertilised 

 eggs produced o-oi cal. per kilo per hour at 12°, 0-02 at 15°, and o-o6 

 at 19°. Pucher studied the changes which take place in the incubated 

 infertile egg during 20 days from laying. He found that the total 

 glucose of the white fell by 90 mgm. per cent, and the total glucose 

 of the yolk rose by 40 mgm. per cent. For purposes of rough 

 calculation, the white may be taken as 33 gm. and the yolk as 16 

 gm., in which case the former loses 30 mgm. in 20 days, and the 

 latter gains 6 mgm., so that the loss from the egg as a whole would 



