19 



Meeting of December 12, 1922 



The meeting of the above date was held in Lecture Room 139 

 of Barnard College. The speaker of the evening, Dr. D. T. 

 MacDougal, discussed "The Constitution and Action of Living 

 Matter.^' 



Living matter, Dr. MacDougal stated, is made up mainly of 

 gums or mucilages, soaps, and lipoids or fatty substances. 

 These substances are mixed together, but are not dissolved in 

 each other, and the intimate processes that constitute life take 

 place chiefly in the liquids which fill the spaces in this comjolex 

 sponge. Twist and tangle together a few hundred short frayed 

 fibers of cotton, silk, wool, and linen, wetted in mucilage, and 

 you will have a model of the invisible structure of protoplasm, 

 magnified many thousand times. 



Our inquiries have been rewarded so far as to allow us to see 

 that the building materials of the protoplasmic city, like brick, 

 stone, metal, boards, and cement, enter sparingly into com- 

 pounds with one another and simply adhere and intermix. The 

 proteins may dissociate to some slight extent, the soaps are known 

 to form several kinds of ions, and these substances liquefy the 

 lipoids; beyond this, substances of the four named groups of 

 colloidal material do not diffuse into each other or dissolve each 

 other, so that they must, upon admixture in a liquid condition, 

 set or form a gel in which the separate substances would form 

 interlaced meshworks. 



Beyond the recognition of such objects as starch grains, oil 

 drops, crystals, etc., as separated material, any distinction 

 between the living and non-living in the cell is purely academic 

 and hence futile to the physiologist. In this connection, refer- 

 ence may be made especially to the wall, which with its lique- 

 fiable pentosans and lipoids may well be regarded as a living part 

 of the cell until it reaches extreme age or highly specialized 

 differentiation. 



Life in the last analysis consists of a series of correlated trans- 

 formations of energ^^, or chains of metabolism, which take place 

 in the liquid occupying the spaces of a colloidal meshwork. The 

 ions and substances concerned in these never-ceasing changes 

 are at all times subject to the surface forces of the particles or 

 strands of tlie meshwork, as modified or determined by the elec- 

 tric charges carried. 



