I\ I 1 kACTIONS OF PROTOPLASMIC MASSES. I IQ 



By referring t<> Table III. it will be seen that cross-fusion be- 

 tween tin- two lines persisted through generations k-s-5 and 

 k-6, while two d.iys later (k-sw-6 and k-8) their potency to fuse 

 with the otlu T'- fragments had teased. On the 2d day after the 

 first negative reaction was observed. linek-5/f was taken out of the 

 sugar solution and placed in the same medium used for line k; 

 nevertheless, tin- reactions between the two lines continued to be 

 of the shattering type for 4 more days; i.e., cross-fusion was not 

 observed again until the fifth day after the two lines had been 

 restored to a common environment (k-s-i4 and k-i6). For 

 the next few days the inter-reactions were positive, but from 

 generations k-5M-2l and k 24 until the experiments were dis- 

 continued, shattering of the protoplasms t<x>k place in every 

 instance. Compare the second shattering periwl with re>ulis 

 shown in Table 1 1 



An interesting jx)int brought out by this study, is the fact that 

 though the normal si/c was regained two days after the individu- 

 als of line k sn were removed from the sucrose solution, the 

 inability to cross-fuse with fragments of specimens from line k 

 persisted for five days. In other similar experiments the stability 

 of this physiological variation as compared to the morphological 

 dillerence in si/e was shown even more strikingly. 



Three other series of experiments, in which I per cent, sucrose 

 was used as the modifying factor, were conducted, and all of them 

 gave results parallel to those shown in Table III. For instance, 

 on June Jth the progenitor of clone M was isolated from a wild 

 culture and upon dividing the next day, lines m and m-sn were, 

 started. Cross-fusion between these two lines was observed on 

 the third day (generations m-4 and m-SM-4), shattering reaction 

 exhibited on the oth (m ~ and m .v//-6), line m su put back in 

 standard culture medium on the 7th, ne^athe inter-. n-iions per- 

 sisted until the i.sth (m-i8 and m-s//-i5 I, then . To^-fu-ii.ns took 

 place during the next five days, all of the interaction- after this 

 were of the shattering type. Twenty observations \\ere made in 

 this series of experiments. 



Observations in clone J, lines j and j -sn were U^im on August 

 27th. Cross-fusion between line j and line j >/< on the 4th day 

 (j-4 and J-S//-5), negative on tin- <>th. ( j <> .md j vw-j), line 

 j VK removed from I per cent, surro-e on oth, ne-.iiive inter- 



