354 THE BIOLOGY OF STENTOR 



6. Grafting 



Ciliates may be said to graft themselves in conjugation or fusion 

 of gametic individuals (e.g. Metopus). Heliozoa reincorporate 

 separated pseudopodia and may fuse together in clumps for the 

 purpose of digesting large food organisms. Doubtless for this 

 reason, heliozoa vv^ere the first protozoa artificially to be grafted, 

 beginning w4th Cienkoweski in 1865. The history of these experi- 

 ments, as w^ell as the generally futile early attempts to fuse amoeboid 

 forms, w^as recounted by Okada (1930) in connection with his own 

 experiments of this type. More recently, Daniels (1951) has been 

 able to fuse giant amoebas, by impaling one cell on top of the other 

 with one needle and breaking the cell membranes together with 

 another. To Gruber (1885a) belongs the credit for conceiving that 

 stentors can be grafted if cut surfaces are brought together quickly 

 before healing. In a few instances he was briefly successful in 

 rejoining cut stentors. Unmindful of Gruber's explorations, 

 Morgan (1901a) forecast Stentor grafting but was unsuccessful in 

 realizing it. Ignorant of both, I independently succeeded in fusing 

 as many as 4 stentors together (Tartar, 1941b), this possibility 

 being suggested at once by the ease with which two stentor halves, 

 left attached by a small strand of cytoplasm, fused together again. 

 That grafting should be successful in some other ciliates is at least 

 suggested by Prowazek's (1901) experience with one Glaucoma 

 scintillans, cut parts of diflPerent individuals being temporarily 

 united under a cover glass. How much may be accomplished by 

 cutting and shifting of parts in forms too small to graft is shown in 

 the excellent experiments of Suzuki (1957) on Blepharisma. 



The method of grafting was explained in my first paper on this 

 subject (Tartar, 1953). Using the cloth-covered slide already 

 described, two stentors are placed in a large drop of methyl 

 cellulose. The stentors are moved quite close to each other. Each 

 animal is then cut with a sharp needle and the wound surfaces 

 opened widely. By using now a blunter needle, from a stock of 

 needles from which the fine tips have become broken, one animal 

 is pushed so that its gaping wound surface is brought firmly in 

 contact with that of the other. An extra thrust will then spread 

 the two wound surfaces a bit so that the temporary membranes 

 which had been formed over them after cutting are broken afresh, 

 and the two animals will then fuse firmly together (Fig. 98A). 



