184 Intracellular Transmission of Characters 



still, in opposition to Haeckel's positive assurance, re- 

 gard the nucleus as an organ of nutrition, ascribing to it 

 an influence on the formation of protein, starch, or other 

 products of assimilation. 



Owing to the influence of the above named investi- 

 gators, attention has been directed, in recent years, more 

 and more to the nucleus. In consequence of this, a series 

 of observations have been made and published, which 

 speak in favor of the fact that the nucleus, although not 

 self -active, still exercises a very great influence on the 

 most important processes in cell-life. On the whole, the 

 conditions observed must, without doubt, be reduced to 

 this, that the hereditary characters, as long as they are 

 latent, are stored up in the nucleus, and become active 

 only in the other organs of the protoplasts. But it must 

 not be forgotten that, in individual cases, there may be a 

 special correlation between nucleus and protoplasm, which 

 must be attributed to specific adaptations, and not to 

 general laws. In the individual case it will usually be 

 very difficult to decide between these two possibilities. 



First, I shall describe some of the conditions empha- 

 sized already by the older investigators. In young cells 

 the nucleus lies in the middle of the cell. With the in- 

 creasing size of the vacuoles, when the protoplasm reaches 

 the so-called foamy state, it remains in that position and 

 is connected with all the parts of the peripheral plasm by 

 bands and strands radiating from it by the shortest lines. 

 This familiar picture, and the considerable size of the nu- 

 cleus in young cells, may have been the first reasons for 

 attributing special importance to this organ. The nucleus 

 does not grow correspondingly with the increasing 

 growth of the cells. It becomes relatively smaller, and 

 the fusion of the vacuoles forces it out of its central posi- 



