1889-90.] MORPHOLOGY AND PHYSIOLOGY OF THE CELL. 257 



in their life-history, it is impossible to say anything more definite than 

 that everything at present determined points out their kinship to the 

 JSporozoa. 



It is of interest here to note the occurrence of supposed nebenkerne in 

 the pancreas of the dog.* Melissinos and Nicolaides found that 

 these are intra- as well as extranuclear forms, sometimes of 

 curious shape and composition. The intranuclear ones, the 

 plasmosomata, may wander from the nucleus into the cell sub- 

 stance, where, as these observers are led to believe from the 

 results of experiments with pilocarpin, they break up into zymogen 

 granules. They deny the correctness of Platner's view, that the appear- 

 ances, from which Ogata was led to believe that nuclear plasmosomata 

 migrate into the cell, are artificially produced, and, in support of their 

 position, they mention that in a quarter of an hour after the adminis- 

 tration of pilocarpin the plasmosomata show all the stages of migration 

 from the nucleus, the extranuclear forms are numerous and zymogen 

 granules are present, while in half an hour after the administration, 

 neither plasmosomata, extranuclear forms, nor zymogen granules are 

 visible. The extranuclear forms, which arise by migration from the 

 nucleus, of the plasmosomata, they call nebenkerne and these they dis- 

 tinguish from others, which are more or less complicated in their 

 structure and composition and which lie in distinct cavities in the cell 

 protoplasm. These latter they think are: (i) excretions of the cell 

 protoplasm ; (2) the remains of leucocytes ; (3) chromatolysed nuclei. 



METHODS OF STUDY. 



I used several methods at the outset of this research but finally gave 

 the preference to one mode of preparation which included either Flem- 

 ming's Fluid or corrosive sublimate as the hardening reagent. This 

 mode of preparation was as follows : 



The animal {D iemyctyhis viridescens, Aniblystoma punctatuin, Pletho- 

 don gliitinosus) was decapitated, the abdominal cavity opened, the 

 pancreas snipped away and immediately dropped into a saturated solu- 

 tion of corrosive sublimate, where it remained ten to fifteen minutes, or 

 into a quantity of Flemming's Fluid, where it was left from one to twenty- 

 four hours, according to the need. The operation of removal was usually 

 done within twenty seconds, this interval including the decapitation 

 process also. The object of this was to prevent any post-mortem 



*Untersuchungen iiber einige intra- and extranucleare Gebilde im Pankreas der Saugethiere auf 

 ihre Beziehung zu der Secretion. Von C. Melissinos. Mitgetheilt von R. Nicolaides. Arch, 

 fiir Anat., und Pliys., Phys. Abth., 1889, p. 317. 



