On the Growth of the Blastoderm of the Chick. 341) 



allied chemical constitution are heated together in sealed tubes with 

 an excess of either phosphorus pentachloride or pentoxide, a series of 

 colloidal substances are formed which, when freed from the con- 

 taminating phosphoric acid, and dissolved in concentrated ammonia, 

 give opalescent solutions that, on evaporating down in vacuo, yield 

 substances closely resembling in physical, chemical, and physiolo- 

 gical properties certain proteids. 



These colloidal substances, although they differ from one another 

 in minor details, are usually distinguished by the following charac- 

 teristics : 



1. They are soluble in warm water, forming opalescent Isevorota- 

 tory solutions. 



2. The resulting solutions yield the principal colour reactions 

 hitherto deemed diagnostic of proteids. 



3. In the absence of salts, solutions of these colloids do not coagu- 

 late on heating. In the presence of a trace of a neutral salt they 

 coagulate on heating at temperatures very similar to proteid solu- 

 tions. 



4. Fractional heat-coagulation shows the colloidal solutions are a 

 mixture of different substances. 



5. The different constituents of the colloidal solution exhibit 

 different physiological action. 



6. In the presence of an excess of neutral salts, or of salts of the 

 heavy metals, the colloidal solutions behave in a manneir similar to 

 proteid solutions. 



7. When introduced into the circulation of pigmented rabbits, dogs, 

 and cats, certain of these substances (viz., the colloids designated 

 A, B, C, a. and ft) produce intra vascular coagulation of the blood in a 

 manner similar to a nucleo-proteid. They also hasten the coagul- 

 ability of the blood withdrawn from the carotid, and will, when 

 slowly injected intravenously in minute quantities into dogs, produce 

 a retardation of the coagulability of the intravascular blood, e.g., a 

 "negative phase." 



8. Apparently these colloidal substances are, owing to both their 

 physical and chemical properties and their physiological behaviour, 

 the nearest synthesised bodies at present known to proteids. 



'An Experimental Examination iuto the Growth of the 

 Blastoderm of the Chick." By RICHARD ASSHETON, M.A. 

 Communicated by ADAM SEDGWICK, F.R.S. Received 

 November 12, Read December 10, l#9b*. 



In* making an experimental study of the growth of the blastoderm 

 of the chick, I had two chief objects in view : 



