508 GENERAL PHYSIOLOGY 



characters. Since, however, the spermatozoon is a complete cell 

 possessing nucleus and protoplasm, nothing in Boveri's experiment 

 has proved that the protoplasm also does not take part in 

 hereditary transmission. The fact that pre-eminently or ex- 

 clusively paternal characters are observed in the larvas ought 

 hardly to cause surprise, since upon the paternal side a whole cell 

 enters into the fertilisation, but upon the maternal side only a bit 

 of protoplasm, which, as is well known, is destined to die because 

 of the loss of its nucleus, and is no longer able to preserve its 

 characteristic features, and consequently not able to transmit 

 them. Hence, in the light of the fundamental fact of the infalli- 

 ble death of non-nucleated protoplasmic masses, Boveri's view, that 

 in his experiment maternal characteristics would necessarily have 

 been transmitted also, if the protoplasm were to take part in 

 heredity like the nucleus, appears unsupported. After all the 

 above we cannot help considering Boveri's experiment wholly 

 indifferent as regards the decision of the question whether the 

 features of the cell that determine its character are contained in 

 the nucleus alone. 



Another form of the supremacy theory is expressed in the view 

 of Eimer ('88), Hofer ('89-90), and others, that the nucleus controls 

 the vital phenomena of the cell, especially the movements of the 

 protoplasm, after the manner of a central nervous organ. Eimer 

 supports his view by various morphological observations, not 

 wholly undisputed, upon the ending of nerve-fibres in the nuclei 

 and even in the nucleoli of cells. But, even if these should really 

 be confirmed, there would be no ground in them for ascribing to 

 the nucleus alone the regulation of the movements of the 

 protoplasm. Hofer believes that from experiments on Amoeba 

 he can draw the conclusion that "the nucleus is a regulating- 

 centre for movement." He cut the bodies of large Amoebae 

 into nucleated and non-nucleated parts. While the nu- 

 cleated parts continued to behave exactly like complete Amoebae, 

 the non-nucleated pieces showed normal behaviour for 15 20 

 minutes only. Then the movements became irregular, the forma- 

 tion of pseudopodia taking place abnormally, and finally wholly 

 ceased. From this Hofer concludes that the protoplasm possesses 

 the power of movement, but that the nucleus is a centre which 

 regulates the movements. That this view cannot be held follows 

 from the striking experiments of Balbiani ('88), who observed that 

 under favourable conditions non-nucleated pieces of Infusoria con- 

 tinue to live for many days with completely unchanged movements. 

 Finally, exhaustive experiments upon various Rhizopoda and In- 

 fusoria} especially upon ciliate Infusoria that perform very complex 

 and characteristic movements, have been directed particularly 

 toward this question, whether the nucleus ought to be regarded as 

 1 Cf. Verworn ('89, 1). 



