274 THE UNFERTILISED EGG AS A [pt. iii 



concentrations of alkali, and which showed that the clot could vary 

 very greatly in its properties, from opacity to almost perfect trans- 

 parency, for instance. Tarchanov had decided that the transparent 

 coagulum of the nidicolous egg-whites was not to be identified 

 with that produced by sodium or potassium albuminate, but Zoth 

 succeeded in showing that the differences were not sufficient to dis- 

 tinguish them. Zoth fully confirmed Tarchanov's finding that ordinary 

 egg-white could be made to pass over into nidicolous egg-white by 

 treating it with i o per cent, potash in the cold for ten days, and was 

 able to explain all the differences between tataeiweiss and alkali 

 ovoalbuminate as due to variations in the amount of alkali present, 

 or rather the amount of cation as compared to anion. It is most 

 unfortunate that we have no detailed ash analyses of the egg-whites 

 of nidicolous birds, for, as will later be seen, the egg-white of the 

 hen has rather more total anion than total cation, and this relation- 

 ship might be expected to be even more strongly marked in the case 

 of nidicolous egg-white, perhaps^ indeed, as much as to counter- 

 balance the excess of cation over anion in the yolk. There can be no 

 doubt, however, that the egg-whites of nidicolous birds are relatively 

 richer in alkali than are those of others, and it is this, combined with 

 their different water and total ash content, which causes the albumen 

 to coagulate differently from those of others. Thus, if 5 c.c. of filtered 

 egg-white from a fresh hen's egg be put in each of three small 

 Erlenmeyer flasks, 2 c.c. of water added to A, 2 c.c. of 0-89 per cent. 

 KOH to B, and 2 c.c. of a mixture of equal parts 0-89 per cent. KOH 

 and 0-66 per cent. NaCl to C, the coagulum in A will be the usual 

 white, thick, solid and opaque mass, while the other two will be 

 transparent like tataeiweiss, slightly opalescent, more or less liquid, and 

 Cmore opalescent than B. It would be interesting to reinvestigate the 

 whole question anew in the light of recent knowledge and technique. 



Another curious effect was noted by Melsens and Gautier. Melsens 

 found that, if a stream of carbon dioxide, hydrogen, nitrogen or 

 oxygen, was passed through dilute egg-white, or if it was shaken 

 violently, a precipitate of fibrous membranous shreds was formed. 

 Gautier observed that about i -5 per cent, of the protein was thus 

 changed; he filtered it off and determined its elementary composition, 

 which showed nothing remarkable. He concluded that a protein 

 which he called " ovofibrinogen " existed in the egg-white, and even 

 suggested that an " ovo thrombin " was present to turn it into "ovo- 



