OSMOTIC GROWTH 



141 



rise in this way to a whole series of amoebiform or vermiform 



productions. 



It must be remembered that in an osmotic growth the 



active growing portion is the gelatinous contents in the interior, 



the external visible growth being only a skeleton or shell. We 



may sometimes succeed in hooking up one of these long 



vermiform growths, breaking the calcareous sheath, and draw- 

 ing out a long undulating translucid gelatinous cylinder. The 



outline of this cylinder is so well defined as to make us doubt 



whether the tine colloidal 



membrane which separates it 



clearly from the liquid can 



have been formed so rapidly, 



or if it may not perhaps exist 



already formed in the interior 



of its calcareous sheath. 



When a large capsular 



shell such as we have described 



bursts, it expels a part or the 



whole of its contents as a 



trelatinous mass which retains 



the form of the cavity. Sinii- 



arlv, if we suddenly dilute 



the mother liquor around an 



osmotic cell, it bursts by a 

 process of dehiscence, and pro- 

 jects into the liquid a part of 

 its contents, which may thus 



become an independent vesicle. In this way a single osmotic 

 cell may produce a whole series of independent vesicles. 



It is even possible to rejuvenate an osmotic growth that 

 has become degenerate through age. An osmotic production 

 avows old and dies when it has expended the osmotic force 

 contained in the interior of its capsule. A calcium osmotic 

 growth which has thus become exhausted may be rejuvenated 

 by transferring it to a concentrated solution of calcium chloride. 

 It will absorb this, and thus be enabled to renew its evolution 

 and growth when put back again into the original mother liquor. 



Fig. 55. — Microphotograph showing 

 the structure of various osmotic stems. 

 (Magnified 25 diameters.) 



(a) Sodium sulphite. 



(/>) Potassium bichromate. 



(c) Sodium sulphide. 



(d) Sodium bisulphite. 



