PHAGOCYTIC ACTIVITY OF THE SPLEEN 441 



are readily detectable by reason of their red staining granules. 

 No color was yet visible in the urine. 



Two hours. At the two-hour period the injected pigeon cor- 

 puscles are no longer recognizable as such, having lost their 

 original form and finally become drawn out and subdivided into 

 smaller and smaller globoid and irregular fragments. That the 

 amount of hemoglobin, either free or still in combination with 

 minute portions of the substance of the corpuscles, is overtaxing 

 the capacity of the organism is shown by the very evident hemo- 

 globinuria. The cells of the liver show many minute brown 

 granules in their cytoplasm. The number of pseudo-eosinophilic 

 polymorphonuclears has increased, often a dozen being seen in 

 one field. A new and larger type of cell, containing red-staining 

 granules, now appears in small numbers, at most two or three in 

 a field. These are cells with a single eccentrically placed nucleus, 

 which has a very well-defined nuclear membrane. Within the 

 nucleus are one or two larger dots of chromatin, but otherwise 

 the chromatin is very finely divided. The shape of the nucleus 

 usually tends to be spherical, but may have one side flattened or 

 slightly concave. An examination of the bone-marrow shows 

 that similar-appearing cells are there in great numbers. They 

 are both in the blood-channels and in the framework tissue, and 

 most of them, though not all, are packed with the red-staining 

 granules. This comparison leads to the conclusion that the new 

 type of cell now appearing in the spleen has come from the bone- 

 marrow and is of the myelocyte type. 



The splenocytes are not greatly different in number or size 

 from before. Some are conspicuous by their multiple brownish- 

 colored inclusions. One of these cells measured 20.5 y. X 12.3 m, 

 which is no larger than splenocytes, containing several inclusions, 

 from the normal spleen. Occasionally a splenocyte is seen con- 

 taining a pseudo-eosinophile, in addition to remains of red blood 

 corpuscles. 



Three hours. At three hours after injection, the pigeon cor- 

 puscles have been reduced to brown-colored masses and clumps 

 of fine particles. Even more intense hemoglobinuria is found 

 than at the preceding stage. Polymorphonuclears and myelo- 



