376 BOTANICAL GAZETTE [November 



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Viscosity of nucleus 



Chambers (5) states that the resting nucleus of marine ova 

 exists in the sol state," and describes how it can be pinched 

 into two droplets which run together on coming into contact. 

 Kite (15) says of the viscosity of the nucleus of the starfish egg: 

 With the exception of the nucleolus, the nuclear substance is all 

 in the sol state." Of the nucleus of Amoeba proteus, however, he 

 says: "The whole of the nuclear substance is a highly rigid and 

 granular gel, the minutest pieces of which show no appreciable 

 change when dissected out in distilled water." 



Although one must be very cautious in assuming that all 

 protoplasm is possessed of the same physical properties as that 

 particular protoplasm examined, yet on general principles it would 

 seem that it is hardly likely that the nucleus of an ovum is very 

 liquid (that is, a sol), and that of Amoeba a highly rigid gel. My 

 observations on the nucleus of Amoeba show that its viscosity is 

 also low, as is the viscosity of nuclei of marine ova (as stated by 

 Kite and Chambers). Results based on the examination of 

 isolated pieces of protoplasm are very uncertain, and that minute 

 pieces of the nuclear substance undergo no change when dissected 

 out into water is quite untenable. 



The nucleus oi Amoeba is rather liquid, but by no means watery, 

 for it possesses a slight degree of viscosity. It is apparently in the 

 sol state. The nucleus when freed from the organism increases 

 in consistency, sometimes slowly and sometimes rapidly. The 

 extremely viscous and in all probability partially degenerate sub- 

 stance of an isolated nucleus is very coherent and elastic, capable 

 of being stretched into fine, barely visible threads. Ultimately 

 the isolated nucleus degenerates into a granular coagulum. 



Changes in protoplasmic consistency 



While protoplasm may be more or less permanently of a 

 definite viscosity (in such forms as Euplotes), yet it does undergo 

 reversible changes. For example, the ectosarc of Amoeba is charac- 

 teristically of a high consistency, yet at the tip of an advancing 

 pseudopodium it becomes temporarily very liquid. Also, in 

 Myxomycetes and bread mold the quiescent protoplasm is very 



