288 WHAT 18 LIFE 



Coulomb's Law. The law that "the mutual force 

 exerted by two charged bodies is directly propor- 

 tional to the product of their charges, and inversely 

 proportional to the square of the distance between 

 the bodies." 



Crystalloids. A name given by Graham to sub- 

 stances that in solution diffuse readily through a 

 parchment membrane or some other septum. 



Dialyze. To separate crystalloids from colloids 

 by dialysis. (In dialysis the crystalloids diffuse out 

 through a membrane into the surrounding solvent, 

 the colloids remaining behind.) 



Dielectric Constant. A term to denote the capac- 

 ity of a substance for transmitting electrical forces 

 or effects to another body or substance by virtue 

 of the mere proximity to it. 



Disperse Phase. The dispersoid in a disperse sys- 

 tem; that is, the colloidal particles that are suspended 

 in a medium. See Phase and Disperse System. 



Disperse System. A colloidal system. 



Dispersion Medium. The continuous phase in a 

 disperse system; that is, the medium in which the 

 colloidal particles are suspended. See Phase and Dis- 

 perse System. 



Electricity and Life, Early Knoivledge of. That 

 electrical phenomena abound in life is knowledge of 

 long standing. An early number of the Philosophical 

 Magazine (Vol. V, Oct., 1799) contains an article 

 entitled: "Observations on Animal Electricity, and 

 particularly that called spontaneous." The writer, 

 J. J. Hemmer, observes: "We are taught by many 

 instances, both ancient and modern, that men, as 

 well as other animals, have exhibited evident signs 

 of electricity; although the ancients, who mention 

 these instances, did not know to what the phenom- 

 enon was to be ascribed." That the human body 



