Multinucleate Cells : An Historical Study {1879-1919). 25 



ovary wall in one of the Araliaceae. " The instances," Treub writes, 

 " of cells with two or more nuclei .... perhaps deserve some interest 

 as exceptions to a rule hitherto believed general. However, they 

 may very well merely be more or less frequent abnormalities, and 

 hence they cannot serve as the basis for any theoretical deduction." 

 Probably Treub's most important discovery was the constant occur- 

 rence of numerous nuclei in the bast cells and laticiferous tubes of 

 a large number of plants. In both types of element the nuclei 

 multiplied by mitotic division. He states that there is a tendency 

 for many, if not all, of the nuclei of one cell to divide 

 simultaneously. 



In the same year Johow (1880) described multinucleate cells 

 in the older tissues of several Monocotyledons. He gave most of 

 his attention to the internodal parenchyma cells of Tradescantia^ 

 in which he believed that the plurality of nuclei arose through 

 amitotic division. Strasburger (1880) confirmed this conclusion, 

 and Tradescantia has since remained one of the classic examples of 

 amitotic division, being used as an illustration of this phenomenon 

 in every botanical laboratory. But, as we have shown in a recent 

 paper,* we believe that many (if not all) of the cases of amitotic 

 division in this plant, which have been figured and described, are 

 merely instances of changes of form in the nuclei, not necessarily 

 bearing any relation either to division or fusion. 



In several other Monocotyledons Johow obtained similar 

 results. He observed lobed nuclei, which he interpreted as cases 

 of amitosis, in the inner tissues of the leaf of Allium cepa, 

 constricted nuclei in the floral axis of Orchis raaculata, fragmented 

 (zergliederte) nuclei in the scape of Tulijoa sylvestris, and nuclei 

 in the petioles of Anthurium sagittatum which were traversed by a 

 narrow hyaline strip suggesting direct division. All these cases 

 we now regard, however, not as instances of amitosis, but as 

 coming under the same interpretation as that which we have 

 indicated for Tradescantia. 



In a later paper (1881) Johow added several other instances 

 of the occurrence of multinucleate cells in the older tissues of 

 Monocotyledons. He observed such cells in the inflorescence axis 

 of Hyadnthus orientalis and in the older leaves of Sempervivum 

 Wulfeni. 



At about the same time Strasburger (1880)- also contributed 

 some observations upon the same subject. Like Johow he- 

 considered that a fragmentation of the nuclei, often leading to 

 a multinucleate condition, was a widespread phenomenon in the 

 older cells of Monocotyledons. In the tissues of Dicotyledons 

 he found nuclear fragmentation to be much rarer. He however 

 figured lobed nuclei in the very old pith cells of Tropdeolummajus 

 and what is probably a pair of nuclei lying closely approximated 



* Beer, R. and Arber, A. (1919). 



