X. 



The Staining of living Nuclei. 



By 

 Douglas H. Campbell. 



It is an almost universally accepted idea that the very fact of the nu- 

 cleus of a cell becoming stained is a certain indication of its death. That 

 this is not the case may readily be proved, and a series of experiments 

 with a number of widely different plants has shown beyond question that 

 it is quite possible to stain the nucleus and at the same time to have every 

 evidence that the cell is still living. 



It is true that the nucleus of a dead cell colors much more readily and 

 intensely than the living nucleus, but it by no means follows that every 

 nucleus that becomes colored is for that reason dead. 



The following observations were made in the botanical laboratory at 

 Tübingen during the summer semester of 1887 under the supervision of 

 Professor Pfeffer , and were suggested by Pfeffer's ^) paper on the ab- 

 sorption of aniline colors by the living cell in which he show^ed that living 

 protoplasm could be stained but did not record the coloring of the nucleus 

 in the plant-cell. 



After experimenting unsuccessfully for some time I succeeded in Und- 

 ing several colors that colored the nucleus more or less deeply without 

 killing it, and as will be seem from the following account not only were 

 resting nuclei stained but dividing ones as well. 



So for as I am aware, there are no other accounts of the coloring of the 

 nuclei of living vegetable cells, although in several cases those of aniraal 



<) W. Pfeffer, »Über Aufnahme von Anilinfarben in lebende Zellen«. Unters, aus 

 dem botan. Institut in Tübingen. 1886. 



