The Life History of Tillma Magna 41^ 



have been prevented in some way from appearing in the proto- 

 plasm of individuals kept on a varied medium. He can not logically 

 compare his results veith those of Calkins for he is not dealing with 

 the same protoplasm, and unfortunately he carried no control 

 series on a hay infusion diet. As a result, although his own con- 

 clusions are not thoroughly established, he has given added proof 

 of the individuality of the protoplasmic reactions of Paramecium. 

 Thus we have all gradations in the response of protoplasm in 

 a state of vegetative exhaustion to an artificial stimulus. The 

 facts of the weak response of the slightly sensitive protoplasm of 

 Tillina stand at one extreme, and the facts of artificial partheno- 

 genesis involving an extremely sensitive protoplasmic condition, 

 at the other extreme. The terms that have been applied to one 

 set of facts must be applied alike to all and as a result they can 

 have no definite meaning. Above all, the facts of the varying de- 

 grees of sensitiveness of the protoplasm of individuals of the 

 same species as well as of different species must be kept in mind 

 in interpreting changes that take place during the life history of 

 an organism. 



The " Kernplasma^' Relationship Theory. 



In 1903, Hertwig stated his theory of the "Kernplasma" rela- 

 tion, which, briefly, is as follows: In a normal condition there 

 is an established balance between nuclear and cytoplasmic mass, 

 brought about by a continual interchange of nuclear and cyto- 

 plasmic material. This balance is unstable, and under certain 

 conditions, such as starvation, overfeeding, or change in tem- 

 perature, it is lost, and there arises an excess of nuclear or of cyto- 

 plasmic material as the case may be. As a result of this abnor- 

 mality, the cell is unable to carry on its ordinary metabolic activi- 

 ties. Finally it falls into a state of depression, which will ulti- 

 mately result in death unless certain regulatory processes take 

 place, which will restore the normal size relations. This normal 

 condition may be brought about by a self-regulatory process of 

 the cell itself, in which the enlarged nucleus gives up some of its 

 excess material to the cytoplasm, or vice versa; or the normal 

 relations may be restored by the introduction of a foreign element 



