3i6 Natural History Bulletin. 



As to the classification of the nuclei of leucocytes, there are 

 at least four varieties. 



1. The ordinary single nucleus, with regular outline, circu- 

 lar or slightly elongated. 



2. Single nucleus, with slight indentations. 



3. Long moniliform nucleus, sometimes with as many as 

 four constrictions. Some of these moniliform nuclei strongly 

 recall the endoplast of certain Protozoa. 



4. Several small nuclei in one cell. These leucocytes, 

 resemble ordinary pus cells, with three and sometimes four 

 nuclei, much smaller than the nuclei of mononuclear leuco- 

 cytes. 



Blood Plaques. 



These are usually called "third blood corpuscles." They 

 are small colourless bodies, usually angular, varying in size 

 from 2// to 4/A They are said to occur in proportion to the 

 coloured corpuscles as i to 20.1 



EXAMINATION OF LEUKEMIC BLOOD. 



In all the examinations of the blood of the patient referred' 

 to on page 311, great care was exercised in order that the facts 

 here recorded may be exact and reliable, and of use in future 

 investigations. More than the usual number of observations, 

 were made in each case. 



Coloured Corpuscles. 



Size. — One hundred coloured corpuscles were measured,, 

 the average size being ^oV? of an inch, more than 8,«. 



The largest were js"?? of an inch, more than ii/^. Only 

 three of these were found after an extended search. 



The smallest was luiirf) of an inch, more than 3//. It was: 

 regular in outline, appeared plainly bi-concave, and had the 

 usual colour. I kept it under observation for some time,, 

 under the impression that it was the result of the disintegra- 



1 Graj's Anatomy, Lea Brother & Co. Philadelphia. 1SS7. p. 3S. 



