FALLACIES AND PUZZLES IN BLOOD EXAMINATION 121 



account of these, and I am quite sure they have perplexed many a student in the Tropics. 



These little red bodies were first described, so far as I know, by Jolly, and bear his name 



alone or are called Howell-Jolly bodies, Plate VI., fig. 16. Ferrata has made them the "Howeii- 



object of study. They are most commonly single, but two may occur, one often being J°"y " bodies 



larger than the other, and they may be combined with punctate basophilia. It is 



important to note that they have been seen in human blood in cases of leukanaemia. 



A study of the normal bone-marrow apparently showed them to be chromatin residues 



from nucleated erythrocytes, but Jolly has recently put forward the view that they are 



probably due to hydration of the stroma or corpuscular membrane, and believes that 



polychromatophilia, granular red cells (seen in unfixed films) and basophilic granulations 



are only different degrees of the same change. One need not go further into this question 



here beyond pointing out that a study of embryonal blood clears up many obscure points in 



blood cell morphology. These nuclear remains, if such they be, stain red with Leishman 



and Giemsa, and green with methyl-green and pyronin combined. A very puzzling 



conjunction, and one frequently overlooked, is a nuclear fragment situated in a basophilic 



red cell which stains blue like a leucocyte fragment (Plate VI., fig. 11). 



Until quite recently the marginal dots of Theiler, found in cases of piroplasmosis 

 in cattle, were doubtless thought by most to bo of this nature, though Theiler himself 

 could offer no explanation regarding them. Now, however, he and Spreull believe them 

 to be of a parasitic nature, and he has named this new protozoon Anaplaama 

 marginale, and apparently definitely proved it to be the cause of gall-sickness (Plate VI., 

 fig. 12). According to Spreull they may occur free in the plasma. Whether or not this work 

 is confirmed, it behoves all workers in the Tropics not lightly to dismiss chromatin-staining 

 bodies in red cells as nuclear remnants, but to find out if they may have any clinical and 

 pathological significance, to look for them in the fresh blood, to test the effects of 

 different staining methods upon them and to carry out suitable inoculation experiments. 

 More especially is this true if they appear to have a selective affinity for any special 

 portion, i.e. the margin, of the host cell. {See also page 345 of this Eeport.) 



Megaloblasts showing polychromatophilia, and especially if their nuclei are under- 

 going degeneration, may be a source of trouble, but the presence of ordinary 

 megaloblasts in the film should clear things up just as the free nuclei of normoblasts 

 are explained by the presence of nucleated reds. In the red cells of birds and reptiles 

 one may encounter the extra-nuclear centrosomes of Eoss, Moore and Walker. They centrosomes 

 have also described them in human corpuscles. They stain bright red with polychrome '" ^'"^'i'^ 



crvthrocvtcs 



methylene blue and occur as single granules, or as little groups of granules often 

 connected by filaments. The result is a kind of star rosette. They occur along with the 

 chromo-linin granulations of these authors and are shown by their methods of vital 

 staining. Ferrata and Boselli have recently described the chromo-linin granulations 

 under the name of the granular thread-forming (fadenformige) substance. 



It is now time to turn to the white cells and see what they can yield in the way 

 of fallacies and puzzles in stained blood preparations. I do not here intend to say 

 anything about the leucocytes of pathological significance, such as myelocytes, which 

 may be present in the peripheral blood, or to describe different kinds of basophiles, 

 mast cells, etc. It seems to me that these are rather outside the scope of this kind of 

 paper, and in any case they can usually be recognised without much difficulty. One 

 wishes rather to deal with fragments from white cells, inclusions in them, curious 

 nuclear changes and conditions which may suggest blood parasites either in leucocytes 

 or free in the plasma and yet derived from them. 



