r J \A C L- \ 

 DIVISION OF NUCLEOLI. 347 



full of nuclei, which often attain the size of the whole 

 original cell. Such formations occur in many tumours in 



FIG. 104. 



such large quantities, that in England a particular species 

 is thereby distinguished, and on the proposal of Paget a 

 inyeloid tumour (medullary swelling) has been received 

 into the classification. This formation is not, however, 

 confined to the medulla of the bones, but occasionally 

 occurs in nearly all situations. 



Muscle, upon irritation, exhibits precisely similar forms. 

 Whilst transversely striated muscles are generally pro- 

 vided with nuclei at certain intervals, though in no great 

 abundance, we find, on examining a muscle in the neigh- 

 bourhood of an irritated part, as for example, a wound, 

 a corroded or ulcerated surface, that a multiplication of 

 the nuclei is going on in it ; we see nuclei with two nu- 

 cleoli ; then come constricted, and then divided, nuclei 

 (Comp. Figs. 23, b, c ; 24, B, C), and so it goes on, until 

 we find in different places whole groups of nuclei lying 

 side by side, in which the divisions have taken place to a 

 large extent, or else whole rows of them, one behind the 

 other. In the most marked cases of this sort the num- 

 ber of nuclei increases to such a degree, that at first sight 

 we can scarcely believe we are looking at muscles ; and 

 that fragments of the primitive fasciculi offer the greatest 



Fig. 104. Cells from the marrow of bones, a. Small cells with single and divided 

 nuclei, b, b. Large, many-nucleated cells. 350 diameters. From Kolliker, ' Mikr. 

 Anat.,' I., p. 364, fig. 113. 



