1894.J MICROSCOPICAL JOURNAL. 363 



I. — HiEMATOBLASTS. 



HsBmatoblasts are shining or lustrous homegeneous 

 globules or disks of a marked yellow color, measuring 

 1.5 and 3.5 micromillimeters in diameter up to nearly the 

 size of fully developed red blood corpuscles. They are 

 juvenile forms of the red blood corpuscles present in 

 large numbers in the blood of the newly born and in 

 small numbers in the blood of healthy adults. I have 

 seen them in small numbers in the blood of a healthy 

 man 63 years of age. They are invariably augmented 

 whenever there has occurred a hemorrhage of some extent, 

 as also after frequent slight hemorrhages. We see them 

 with great regularity in urine holding red blood corpus- 

 cles to a varying number due to hemorrhages induced by 

 tumors of the bladder, especially benign papiloma, or 

 hemorrhages from the pelvis of the kidneys due to so-call- 

 ed renal calculi. Their number varies according to the 

 severity and frequent repetition of the hemorrhages. I 

 have seen them in numbers exceeding the number of the 

 red blood corpuscles. They have nothing to do with 

 wasting diseases such as tuberculosis, cancer, syphilis, 

 etc. Neither are they augmented in numbers in chlorosis. 



This I think goes far to prove that hsematoblasts are 

 juvenile forms of red blood corpuscles and their most 

 characteristic feature is their yellowish color due to the 

 presence of haemoglobin even in the earliest recogniz- 

 able stages when they do not exceed the size of a granule. 

 I have stated before that hsematoblasts are homogeneous 

 and apparently structureless.. This is true only of the 

 smallest forms. 



As soon as they have reached a diameter of about 3 

 micromillimetres with a power of the microscope of 1,000 

 to 1,200 diameters, we recognize in them an extremely 

 narrow and faint reticular structure after their exposure 

 to a solution of 1-5 of 1 per cent of chromic acid, or a 40 to 

 50 per cent of saturated solution of bichromate of potash. 



