MUSEUM OF COMPARATIVE ZOOLOGY. 371 



meridional striation ; but this, he thinks, in no way invalidates his pre- 

 viously expressed views. 



In two points he dissents from Strasburger's conclusions : (1.) the 

 process of the neoformation (Neubildung) of nuclei ; (2.) the method of 

 their increase. He maintains that the nucleus is at first a sort of vacu- 

 ole, — a droplike accumulation of a " dickfliissig," clear, homogeneous 

 substance, in a cavity of the protoplasm, which has at first no special 

 limiting layer. Subsequently, the protoplasm in immediate contact 

 with the surface of this nuclear drop becomes compacted into a special 

 " Wandung," — the nuclear membrane, — and one or several nucleoli 

 are formed by a gradual agglomeration of finest spherules. He believes 

 Strasburger's view — that the nucleus is only a more or less sharply seg- 

 regated portion of the cell protoplasm — rests upon a misconception of 

 the true nature of the structures which he has called " cell " and " nu- 

 cleus " in the endosperm cells especially of Phaseolus multiflorus. Ac- 

 cording to Auerbach these are respectively nucleus and nucleolus. This 

 revision of Strasburger's conclusions he endeavors to substantiate by an 

 examination of the properties of the structures in question. In the first 

 place Strasburger's "nuclei" are typical nucleoli, which, in small nuclei, 

 are always dark, solid spherules in the centre of the nuclear space, and 

 which undergo the changes ascribed by Strasburger to his "nuclei," — 

 becoming' often irregularly pointed and vacuolated, whereas nuclei are 

 uniformly clear bodies in dark protoplasmic surroundings. Again, his 

 "cell" cannot be a cell, since from the beginning it is a vesicle (Hohl- 

 blaschen), whereas a free-formed cell is never a vesicle at first. The 

 radial appearance and netlike structure of this "cell" are not necessarily 

 to be homologized with the netlike distribution of protoplasm so com- 

 mon in plant cells, since the same morphological condition is also known 

 to exist in the nucleus of many (animal) cells.* Finally, there exists 

 between these free-formed " cells " portions of the protoplasm of the 

 mother cell. If the wall of the vesicle is the " Hautschicht " of a cell, 

 one must assume that this protoplasmic mass, in which the cellulose 

 membrane is formed, intervenes between the Hautschicht on the one 

 hand and the cellulose membrane on the other ; but that would be alto- 

 gether anomalous. 



The views here expressed concerning nuclear division are substan- 



* Auerbach does not consider the network in this case to be composed of the same 

 substance as nucleolus and nuclear membrane ; instead of being nucleolar substance, 

 it is of the same material which in other nuclei makes its appearance in the form of 

 discrete spherules, — his so-called Zwischenkiigelchen. Compare Auerbach '74. 



