TECHNIQUES 359 



the granular carbohydrate reserves which tend to obscure them. 

 Soon after this operation the stentor will appear entirely normal 

 but lacking the macronucleus. 



Comandon and de Fonbrune (1939b) devised a method and 

 instrument for transferring the nucleus of one amoeba into the cell 

 of another. Essentially, the nucleated cell is pressed against the 

 enucleate one and the nucleus pushed through from the donor 

 into the host. In Stentor the procedure is different. A healed, 

 enucleate specimen is returned to a drop of methyl cellulose along 

 with the donor of the new nucleus. The two animals are brought 

 adjacent with the eyelash. The nucleated specimen is then cut 

 open as described and one or more macronuclear nodes are teased 

 out of the cell without ectoplasm but within a thin halo of endo- 

 plasm. This endoplasm quickly forms a membrane around itself 

 which serves both to preserve the nucleus from exposure to the 

 medium and to form a means of transfer. The enucleated cell is 

 then cut open and considerable area of free endoplasm is exposed. 

 The free sac of nuclear nodes is picked up with the point of the 

 needle and broken against this endoplasm, whereupon fusion occurs 

 and the nodes are taken in (Fig. 99B). Whole macronuclei can be 

 transferred in the same manner with minimum endoplasm if 

 dividers with compacted nuclei are used as donors. Healing of the 

 host wound firmly traps the nucleus within the cell. Nuclear 

 transfers are possible between different species of Stentor, and it 

 can be seen that the foreign nucleus is not ejected but persists in 

 the alien cytoplasm. 



The possibility of other techniques should be explored. For 

 instance, it would be desirable to find a non-toxic agent which 

 would permit healing but prevent intimate rejoining of cut edges 

 of the ectoplasm so that stentors would remain as cut; or to 

 discover a means of agglutinating stentors so that they adhere by 

 the ectoplasm without fusing. In the first case, would a mincerated 

 stentor express multiple individuality, and in the second could the 

 impulse to primordium formation be transmitted by contact from 

 cell to cell ? Possibly stentors could be grafted by drastic methods 

 not involving individual handling. I have tried forcing highly 

 concentrated coerideus through the finest stainless-steel screens 

 available. A few fusions were made in this way but not large 



