724 PROCEEDINGS OF SECTION K. 



of fragments from them, down to the small spherical bodies ob- 

 served in the general circulation. I have also examined the blood 

 of a number of very young rodents, and find that the chromatin 

 bodies present in their erythrocytes are indistinguishable from 

 those herein discussed. 



The evidence at present aj^pears to be greatly in favour 

 of the view that the chromatin bodies observed in the erythrocytes 

 of marsupials, lemurs, mouse-deer, capachin monkey, and 

 orang-utan . cannot be classified with the anaplasms, but 

 should be placed with the bodies of Jolly. One cannot, however, 

 accept the view of this observer as to their origin, viz., that they 

 are due to the hydration of the stroma of the corpuscle. They 

 appear rather to be purely nuclear remnants. One has to admit, 

 however, that at present there is no certain method of distinguish- 

 ing microscopically between the anaplasms and the Jolly bodies 

 when they appear in the circlilating blood. 



The question then to be answered is, if these bodies are non- 

 parasitic, what is the cause of their appearance in the blood of 

 animals to which they are not normal 'I 



The case of the marsupials must be discussed separately, as 



I have already given my view that the presence of chromatin 



bodies in the red cells of these animals should be considered 

 normal. 



With the other animals, the condition appears to assume a 

 pathological aspect. It is known to every one liere that the red 

 cells of the mammalian embryo are nucleated, but that the nucleus 

 disappears from the red corpuscle in the general circulation dur- 

 ing late foetal life. Erythroblasts, however, persist in the bone 

 marrow of the adult. In health, nucleated i*ed corpuscles are not 

 seen in the circulating blood, but if any condition exists that 

 causes the number of red cells to fall greatly below that of normal, 

 there is usually a corresponding activity on the part of the erythro- 

 blasts and an attempt to make up the deficiency. As a result, 

 some immature nucleated red cells (normoblasts, &c.), are thrown 

 into the circulating blood from the bone marrow. Seeing that 

 this is the case, one could explain the presence of only fragments 

 of the nucleus in the red cells of the circulating blood by con- 

 sidering that some pathological condition exists in which there is 

 a constant, but not great drain upon the red cells, the destruc- 

 tion, however, being well above tlie normal. The resulting stimu- 

 lation is not great enough for red cells with entire nuclei to be 

 thrown into the general circulation, but yet it is sufficient for 

 some cells that have not had time to discard the last remnant of 

 the nucleus, and consequently such may be demonstrated in the 

 blood. 



