1906.] Observations on the Life-history of Leucocytes, 493 



The thread, which subsequently breaks up to form the granules, has only 

 been met with in the cells in the bone-marrow, and has not been observed in 

 leucocytes anywhere else in the body. 



It would seem, then, that the granules arise from a threadwork 

 forming part of the archoplasm, and which is probably derived from it 

 originally. This thread grows and eventually breaks up to form the 

 granules. During the whole of its existence it stains with a basic stain, 

 reaching the maximum in staining capacity shortly before it breaks up. 

 The staining capacity of the nucleus during this period seems to vary 

 inversely with that of the thread. There seems to be no appreciable 

 difference between the material forming the thread and the chromatin in an 

 actively dividing cell. There is, however, no evidence of its having been 

 derived from the nucleus. 



The position, from a cytological point of view, is much obscured by the current 

 methods of dealing with leucocytes. It is extremely difficult to compare the 

 results obtained by the methods used by cytologists with what has been 

 observed in specimens that have been dried, heated, fixed with alcohol, 

 or otherwise treated in such a way as to materially alter the appearance and 

 inter-relationship of the parts of the cell. The methods commonly used, 

 however, have proved to be of the greatest value clinically, and with regard 

 to the staining reaction of the granules, which have so largely entered into 

 the current classification of leucocytes, there is nothing incompatible with 

 the observations here recorded. 



It has been seen that the staining reaction in some, at any rate, of the 

 granular cells changes from basic to acid. It is highly probable that this 

 change may be hastened or retarded by influences external to the cell while 

 it is still in the body. This probability is increased by the fact that the 

 proportion of acid to basic staining granules is increased by so crude an 

 influence as additional heat and dryness after the cells have been removed 

 from the body. 



The presence, therefore, of varying proportions of cells containing the 

 so-called acidophile and basiphile granules in different diseases is just what one 

 would expect, and is no argument against a common origin of both from the 

 thread here described as occurring in some of the cells in the bone-marrow.* 



* The material used has been chiefly obtained from the guinea-pig and rat. The 

 same fixatives were used as described in " Observations on the Life-history of Leucocytes" 

 (' Roy. Soc. Proc.,' 1906). Attention is also drawn to the remarks upon preservation in the 

 same paper, as smears or films of bone-marrow will not show the figures here described. 

 No matter how carefully a smear or film be prepared, there must always be a grave risk 

 that the cells will be partially dried, and the least approach to drying is fatal to the proper 

 preservation of the cells. 



2n 2 



