THE LIVING SUBSTANCE. 



33 



elusion, interpenetrated by filose processes ; while the external 

 layer had the value alike of ectosarc, and of a pellicle or pelli- 

 cular membrane. 



Those leucocytes whose first position was nearer the center 

 of the mass, behaved quite differently from those of the periph- 

 ery. They coalesced changefully into ever-increasing lumps 

 and masses of protoplasm, spinning threads and webs in all 

 directions, even to the very periphery where they joined 

 themselves to those units forming the membrane. 



There seemed to be shown here an organized effort on the 

 part of members of the artificially formed colony to make an 

 inchision of the serum, and so to retain for the common sub- 

 stance its accustomed environment as long as possible. (See 

 Selection of Environment.) 



In the second class of structures, cited above as having per- 

 sistent vitality ; the inclusions being already of an organized 

 homogeneity in character, the power of the substance to vary 

 local viscosity, and to maintain it, is thus emphasized, and 

 necessary local food, or stimulus, is better conserved and con- 

 trolled. 



In preparation for encysted states an envelope of increased 

 viscosity is first formed ; sometimes there is merely increased 

 viscosity of the pellicular membrane of the organism ; some- 

 times a separate membrane is formed by exudation, or possibly 

 spinning phenomena, but this latter in these cases I have not 

 seen. Echinus eggs were seen to form membranes by filose 

 phenomena of the pellicular stuff. 



The breaking up of the original mass of a Protozoan into 

 swarm-spores, or into macrospores, is possibly another mode of 

 using a more viscous and finely organized state of the elements 

 for preservation of the substance ; for these products are 

 always surrounded by a very viscous and finely structured 

 area, and, moreover, are supplied with motile appendages 

 which are also tactile and prehensile, by whose means the 

 substance seeks a new and more favorable environment for 

 itself. 



[28] I have observed in all young of Protozoa a markedly 

 greater resistance to adverse environmental conditions ; a tem- 



