890 



two concentric parts, wliich however is not the result of a concen- 

 tric division, but of abnormal branching. 



If moreover we consider that we have to do with fibres which 

 are strongly proliferating, take as evidences the hypertrophy, the 

 longitudinal divisions and the presence of a great number of young 

 fibres, it may be clear that this process is nearly related to the 

 well known lateral buddings of niuscle-übres the so called "Muskel- 

 knospen" of Neumann, especially because the before mentioned second 

 observation of Ekb already informed us of the encircling of muscle 

 fibres by elements which have grown out of these "Muskelknospen." 



Therefore I should wish to conceive the peripheral mantle of the 

 fibres as a complex of defectively developed and abnormally grown 

 lateral branches. 



With this conception it is easily understood that the circular fibrils 

 often appear only on one or more spots of the fibre, and leave 

 sometimes a great deal of the fibie free; it is just as well compre- 

 hensible that on transverse sections we generally see a narrow 

 fissure between the central and peripheral fibrils, moreover it will 

 be clear that sometimes out of these fibres originate very thin 

 muscle-elements, which can be followed into the surrounding fibrous 

 tissue, whilst finally it becomes explainable that the peripheral fibrils, 

 abnormal of origin as they are, sooner undergo degeneration than 

 the central fibrils which form the real fibre. 



This conception leaves of course many facts unexplained : first of 

 all is it not clear why these fibres should give off so many abnormal 

 branches, and why their nuclei have swollen so peculiarly and taken 

 the form of vesicules, while the nuclei in the surrounding fibres 

 are much smaller and more solid ; finally the curious behaviour 

 of the fibres with regard to degenerations is still unexplained : while 

 the surrounding fibres undergo "Zenker" degeneration, we see here 

 rather constantly the above described peculiar reducing of the fibrils 

 to very fine threads and grains. 



All this cannot be quite accidental, because these alterations 

 appear too regularly ; I could not find however a satisfactory 

 explanation for these facts. 



We now come to the question how this abnormally proliferated 

 tissue must be considered: is it allowed to classify it among the 

 tumours or not? 



Macroscopically it looks quite like a tumour, but we shall see that 

 after microscopical examination this diagnosis cannot be sustained ; 

 firstly we find in rhabdomyoma always very small muscle-fibres 



