SECT, i] PHYSICO-CHEMICAL SYSTEM 273 



duck, goose, guinea-fowl, partridge and corncrake had ordinary 

 white. This classification agreed roughly with Davy's high and low 

 coagulation points for the egg-white, and corresponded on the whole 

 to Morner's two classes, the former having ovomucoid not precipit- 

 able with percaglobulin and the latter having the precipitable 

 variety, but to this there were some exceptions; thus the plover's 

 ovomucoid could be so precipitated, but its egg-white was tata 

 and it yet produced fully-feathered chicks. It was, however, the only 

 exception to Tarchanov's generalisation, (It should be explained 

 that the word tata was derived from the name of Tarchanov's small 

 daughter.) Tarchanov found that tata egg-white was about 3 per 

 cent, richer in water than the other kind, a conclusion which Morner's 

 later analyses did not confirm. He also said that it was alkaline to 

 litmus, but became less so as the tata eggs developed. This agrees 

 with the later classical work of Aggazzotti on the reaction of the egg- 

 white of the hen's egg during its development. Tarchanov reported 

 that tata egg-white could be made to coagulate at ordinary tempera- 

 tures by the addition of a little potassium sulphate, and that it would 

 itself coagulate if the temperature was raised well above the boiling- 

 point of water. It was, he said, more easily digested by enzymes, it 

 putrefied more readily, and during development it changed into a 

 form resembling ordinary egg-white. He made some studies on its 

 secretion by the oviduct of these birds, and was the first to perform 

 the experim.ent of putting a ball (in his case a lump of amber) at 

 the top of the oviduct and seeing it emerge at the bottom with layers 

 of egg-white and a shell secreted around it. The change during 

 development from tata to ordinary egg-white Tarchanov found he 

 could imitate by bubbling carbon dioxide through the original white, 

 after which it would coagulate in the usual way. On the other hand, 

 he found that if he soaked normal hen's eggs in a 10 per cent, solu- 

 tion of alkali the white took on the properties of tata egg-white, and 

 became just like the glassy material in the sand-martin's egg. He 

 suggested some relation between these phenomena and the alkali- 

 albuminate of Lieberkiihn, but did little to determine its chemical 

 relationships. He was unable to get any development in the case of 

 hen's eggs soaked in alkali. 



In 1 89 1 Zoth took up the whole question of tataeiweiss once 

 more. He was led to do so on account of some researches which he 

 had been making on the effect produced on serum-clotting by various 



