386 THE FORMS OF CELLS [ch. 



the liquid into a thin thread as they completed their spherical f^rm 

 and receded from one another: the reason being that, after the 

 thread or "neck" has reached a certain tenuity, internal friction 

 prevents or retards a rapid exit of the fluid from the thread to the 

 adjacent spherule. It is for the same reason that we are able to 

 draw a glass rod or tube, which we have heated in the middle, into 

 a long and uniform cyhnder or thread by quickly separating the 

 two ends. But in the case of the glass rod the long thin thread 

 quickly cools and sohdifies, while in the ordinary separation of a 

 liquid cylinder the corresponding intermediate cylinder remains 

 liquid; and therefore, Hke any other liquid cylinder, it is liable to 



Fig. 113. Dew-drops on a spider's web. 



break up, provided that its dimensions exceed the limit of stability. 

 And its length is generally such that it breaks at two points, thus 

 leaving two terminal portions continuous and confluent with the 

 spheres, and one median portion w^hich resolves itself into .a 

 tiny spherical drop, midway between the original and larger two. 

 Occasionally, the same process of formation of a connecting thread 

 repeats itself a second time, between the small intermediate spherule 

 and the large spheres; and in this case we obtain two additional 

 spherules, still smaller in size, and lying one on either side of our 

 first little one. This whole phenomenon, of equal and regularly 

 interspaced beads, often with little beads regularly interspaced 

 between the larger ones, and now and then with a third order of 

 still smaller beads regularly intercalated, may be easily observed 

 in a spider's web, such as that of Epeira, very often with beautiful 

 regularity — sometimes interrupted and disturbed by a sKght want 

 of homogeneity in the secreted fluid ; and the same phenomenon is 



