INTERACTIONS OF PROTOPLASMIC MA.-SES. 1 U 



Individuals from the two lines of these clones were confined in 

 the same concavities for ten days. During this time frequent 

 tests showed cross-fusion in every instance: consequently on 

 \o\emlier 10 the related lines were separated again. by placing 

 the individuals in different Petri dishes containing 25 cc. of 10 

 PIT 1 1 nt. hay infusion. At intervals of two week> the number ot 

 indi\ idti.ils in the Petri dish cultures were estimated, and the 

 approximate number of generations represented determined. 

 Then fresh Petri dish cultures were made, and thus the lines were 

 perpetuated until January 5, 1923. l On January 5 tests were 

 made for cross-fusion between the two lines of these clones, with 

 the result that all of them gave the shattering reaction. Then an 

 individual from line j was put in a concavity with an individual 

 from line jd. In a like manner the two lines of the other clones 

 were brought together. During the next five days the inter- 

 protoplasmic reactions were universally negative, while on the 

 sixth day they were all positive. Cross-fusion between the re- 

 lated lines continued until the experiments were stopped on 

 January 15. At that time clone J had been observed for 188 

 generations, clone K for 200, clone Q for 126, and clone R for 122. 



These results present a strong argument in favor of environ- 

 ments as the principal modifying agent; but the skeptic miijit 

 say that perhaps the two lines were confused while being kept 

 in the same container, and what seemed to be cross-fusion be- 

 tween very distantly related individuals was really positive inter- 

 actions of very closely related specimens. That such was i he 

 case is very improbable; for in the first place, especial care was 

 taken tc^avoid that error, and secondly, the results obtained were 

 too uniform. The same mistake would hardly have been made 

 in every experiment at the same time. However, the most con- 

 \incing evidence obtained was made po il>le by the Midden 

 appearance of a double form in a Petri di>h culture <>1 rlme O, 

 line qd. This abnormal specimen was di-< -\ ered <>n \n\rinU T 

 21, 1922, and seems to have appeared l>e..uiM- i.t" the failure of 

 the shells to completely separate at the time of ii--.it m. It is 



1 An objection might be raised to mass cultun-s mi tln-gri>mid- that i"ii 



illicit take place between some of the organism-, thus disturbing the germinal 



.cncy of the individuals concerned. ThU ]> . ibiliiy 



linn and guarded against, and it can be said with .1 :i ili>l nut 



place among the specimens used in this invi--ti.iMtiiin. 



