1029 



but the iieuro- fibrils appeal- exceedingly distinct!}'. One may tlins 

 postulate that if processes of the cells in this colony had i-eally 

 existed, they would also have clearly appeared in the sections. That 

 these cells are likewise at an eaily stage in their development is 

 indicated, in addition, by the fact that there are evident bridges of 

 protoplasm between some of them. In this series of sections there 

 are, however, colonies of cells which, as fai" as one can judge, are at 

 later stages in their development — in these the different cells have 

 processes, there are no bridges of protoplasm between them, and 

 the future ca|)sules of the separate cells exhibit the first traces of 

 their development. In the cells of some of the colonies found in the 

 3,5 yeai- old dog I have been able to show processes — there were 

 also signs showing that these colonies were at a later stage of 

 development than the one shown in fig. 4. In the five year old dog, 

 as has been mentioned above, I found only a single colony of cells 

 and no apolar cells. The results of counting the ganglion cells and 

 their axons indicate, however, that there really are apolar cells here 

 as welP). The purely mor|)hological observations in the 3.5 and 

 5 year old dogs do not, of course, quite exclude the |)0ssibility of 

 there being colonies of cells here as well at a very early stage of 

 development, but with i-egard to this they indicate that in older 

 animals these formations are relatively very rare. It is to be noted 

 that such eminent investigators as Key and Rktzius''), Schwalbe') 

 and of recent years Ranson '), are decidedly against the opinion 

 that apolar cells are to be found in the spinal ganglia on the other 

 hand. Kölliker*), Muller") and others hold the opinion that such 

 cells really exist. It would lead me too far fi-om my real subject 

 were I to discuss in detail the literature concerning apolar cells in 

 the spinal ganglia. I must content myself with the references already 

 given, and in connection with this point I wish to state that there 

 are also investigators who have observed processes from cells in 

 colonies similar to those described above; such are Ahndt') and 

 Stienon *) etc. 



1) These and other explanatory details will be given more fully in a forllicoining 

 and more complete work. 



2) Key and Retzius. Studiën in d. Anat. d. Nervensyst. u. Bindegewebe, Bd. 2, 

 1876. 



?) ScHWALBE, Arch, f Mikr. Anat. Bd. 4; 1868. 



■*) Ranson, L. c. 



^) KöLLiKEE, Handbuch der Gewebelehre, 5 Aufl., 1867, quoted from Muller E. 



6) Muller, E., 1. c. 



7) Arndt, Archiv f. Mikr. Anal-, Bd. 10, 1873. 



S) Stienon, Annales de l'universilü libre de Bruxelles, 1880, quoted from Muller E. 



