mollgaa^d's reticulum 339 



ent twenty-five seconds after decapitation. It has been previ- 

 ously mentioned that in nerve cells of imbedded tissue the Nissl's 

 bodies and neurofibrillae were found in tissue fixed twenty-two 

 seconds after death. It has been stated too that the smear prep- 

 arations do not permit of the detailed study that sections do. 

 It is therefore unnecessary to discuss the various details of obser- 

 vation noted under this heading. It is particularly the time 

 element with which we are here concerned. Mollgaard found 

 no Nissl's bodies or neurofibrillae in freshly-frozen and fixed 

 nerve cells. He considers at least seven minutes post-mortem 

 change, followed by several hours of slow alcohol fixation, neces- 

 sary to produce the Nissl's bodies even imperfectly. But the 

 results submitted in the present paper prove that in unfrozen 

 smear preparations (which have the advantage of excluding the 

 production of artefacts by freezing and allow immediate fixation) 

 both the Nissl's bodies and the neurofibrillae are found in tissue 

 fixed less than half a minute after decapitation, while the cells 

 are still practically in a living condition. Hence Mollgaard's 

 contention that Nissl's Ixtdies are produced by post-mortem 

 change and slow alcohol fixation is totally wrong. The freezing 

 is responsible for his misleading results. 



Whether the sojourn in the fixative be comparatively long or 

 short seems to have no noticeable influence on the Nissl's bodies. 

 In smears taken at various intervals after death the Nissl's bodies 

 show no appreciable change till about twelve to eighteen hours 

 post-mortem, when they gradually begin to disintegrate. To 

 determine whether the alcohol fixation could in any way be 

 responsible for the presence of the Nissl's bodies in the freshly- 

 fixed cell, some smears, instead of being dropped into the fixa- 

 tive, were immediately consigned to the toluidin-blue stain, after 

 which they were carefully washed, mounted in water, and stud- 

 ied. Such smears show the Nissl's bodies to be imdeniably 

 present. They show distinctly, but it seems that they are some- 

 what more granular and possibly a little more diffuse than those 

 of cells fixed in alcohol. In this connection it may be mentioned 

 that Dogiel ('96) stained the Nissl's bodies in unfixed nerve 

 cells, with dilute solution of methylene-blue in warm physio- 



