The relui HUIS ut nutdilinmliia .-iiid other ryti)|)I;iMiiir cciiihtitueiit.s L-U:. 497 



1 *'/„ ;i(|ii('()iis Sdliilidii of pyroiiiii. iiciitr;il n-d. inliiidin Idiic, (fig-. 9), or 

 ili a satiii'iitcd a(|Ucuiis Miliitioii di v;iii;iiiiii : |,iii L'ri';it caiv must be 

 taken in tlic identilicatioii and inici {urial inn of cfll ^i-aiiulations 

 after tlicy have passes tlirong-li such a cnniiilicatcd ami (h->tiii(:tive 

 method as tliis. The caimis may he (himnistrated in the sanie celi 

 tojH'ether with the neurotibrils by staining- it in a satuiatrd aiiueous 

 solution of safranin and differentiating in 95"/o alcohol. They appear 

 as clear spaces winding- in and out between the neurofibrils against 

 a bright red background composed largely of Nissl suljstance (fig. 8). 

 In iron hematoxylin (fig. 2), i\ltmann and copper chrome hematoxylin 

 preparations the neurofibrils and the mitochondria may be distinguished 

 side by side in the axone and their indi\idualit.\- established. Fig. 1 

 is from a preparations made by Bensley's acid fuchsin-toluidin blue 

 method and it shows, even more clearly, the mitorhondria in red and 

 the neurofibrils in brown. Furthermore, in specimens prepared by 

 the erythrosin-methylene blue method of Held the neurosomes (type I) 

 and the neurofibrils appear together in the axone and axone hillock 

 (fig- 13j. 



6. Conclusions. 



1. Mitochondria occiur in adult spinal ganglion cells of the pigeon, 

 where they may be demonstrated by means of all the methods in 

 use for their study in other than nerve cells (p. 480). 



2. The neurosomes of Held are not a single, separate, and 

 distinct form of cell granulation. They may be divided into two types. 

 Type I consists of those which Held observed by the application of 

 his erythrosin-methylene blue method the nature of which is unkno-\Mi; 

 and type II is composed of the rod shaped bodies wliieli he >tudied 

 in his Altmann and iron hematoxylin preparations. There type II 

 neurosomes are mitochondria (p. 479). 



3. There are four fundamental known components in the cyto- 

 plasm of nerve cells, which, in the adult at least, are morphologically 

 independent, and which are not transformed one into another, either 

 by fixation or in any other way. namely: the mitochondria, the Mssl 

 bodies, the canalicular system and the neurofibrils. The mitochondria 



Internationale Monatsschi'ift f. Auat. u. Pliys. XXIX. 32 



