102 OEIGIN OF COLORED BLOOD-CORPUSCLES. 



Lumps of living matter, however, separated from the neighbor- 

 ing formations and suspended in plasma, in blood-vessels, I still 

 considered as blood-formers haematoblasts. 



The idea prevailed at that time that red blood-corpuscles 

 originate from nucleated, colorless corpuscles, although no other 

 support was found for this idea except that in the embryo there 

 are numerous nucleated corpuscles in the blood-vessels. All 

 attempts to transform colorless into colored blood-corpuscles 

 outside the body, by their exposure to oxygen gas, proved to be 

 failures. I have shown that whenever one tissue is transformed 

 into another, f. i., cartilage into bone, and also in an inflamed 

 tissue, f. i., that of bone, colored blood-corpuscles grow from 

 granules of living matter in a way entirely different from that 

 supposed by other histologists. 



E. Neumann* first drew attention to a difference in the 

 shape of the corpuscles of the medulla of bone. In the liquid 

 pressed out of this tissue he found colorless, granular lymph- 

 corpuscles and yellow corpuscles, characterized by a homogeneous 

 appearance, and a size only a little exceeding that of red blood- 

 corpuscles. He met with colored cells in the medulla of bone, 

 in numbers the greater the younger the individual, and inter- 

 preted these to be stages of transition to red blood-corpuscles. 

 He also concluded that during life a continuous transformation 

 of lymphoid into red J)lood-cells takes place. 



G. Bizzozero t found in the medulla of bone, besides colorless 

 protoplasmic bodies, such with homogeneous, reddish-yellow 

 nuclei, and also bodies about to divide, which contained two 

 homogeneous reddish-yellow nuclei. He also interpreted these 

 bodies as transitions of colorless to colored cells, and came to 

 the conclusion that the medulla of bone was of importance in 

 the production of colorless and red blood-corpuscles, and 

 that the formations of the latter started from the nuclei of 

 the former. 



It is obvious that the formations described by these investi- 

 gators are identical with those I had termed haematoblastic, 

 which occur not only in the medulla of bone, but also in bone 

 and cartilage in the normal process of ossification. The yellow 

 lumps which all of us have seen are by no means blood-cor- 

 puscles, though under certain circumstances they may furnish 

 the material for the formation of blood-corpuscles. 



* Centralblatt f iir die med. Wissenschaften, 1868. Archiv der Heilkunde, x. 

 t Gazetta medica Lombarda, 1868 and 1869. 



