

DEVELOPMENT OF THE EED DISKS. 237 



GLOBIN. 



This name has been given by Preyer to the proteid part of 

 the haemoglobin, on account of its slightly differing from globulin, 

 though it resembles it in being precipitated by the weakest acids, 

 even carbon dioxide. 



CHEMISTRY OF THE STROMA. 



The stroma forms only about 10 per cent, of the solid parts of 

 the corpuscles, the rest being hsemoglobin. The proteid basis of 

 the stroma is probably mostly made up of a globulin, also con- 

 taining lecithin, cholesterin, and fats in minute proportions. There 

 is little more than one-half per cent, of inorganic salts in the 

 red blood corpuscles, of which more than half consists of potassium 

 phosphate and chloride. 



DEVELOPMENT OF THE RED DISKS. 



In the early days of the embryo the bloodvessels and corpuscles 

 appear to be formed at the same time from the middle layer of 

 the blastoderm (mesoblast). They first consist of round, nucleated, 

 colorless cells, which subsequently become colored, gradually lose 

 their nucleus, and assume the characteristic shape of the red cor- 

 puscles, the rest of the original mass of protoplasm remaining as 

 a rudimentary bloodvessel. 



In the later stages of embryonic life the red corpuscles are said 

 to be formed in the liver, possibly out of protoplasmic elements 

 which are made in the spleen and thence carried to the liver by 

 the portal circulation. 



In the connective tissue of rapidly growing animals tadpole 

 (Kolliker), rabbit (Ranvier), rat (Schafer) certain cells can be 

 seen to be connected in the form of a capillary network, and within 

 the protoplasm of these cells red coloring matter is developed, and 

 the particles of color can soon be recognized as characteristic 

 blood corpuscles, arranged in rows within the newly-formed net- 

 works. Thus isolated small networks of capillaries, consisting of 

 a few meshes filled with blood corpuscles, are formed independently 

 of the general circulation. 



