168 MacDOUGAL and SPOEHR— components AND 



Some mention of this action of glycocoll has already been made 

 in a previous article, but the effects shown by agar-gelatine mixtures 

 in which the two principal components vary between 40 and 60 per 

 cent, were so marked that attention was again directed to their 

 measurement and to the formulation of some ejsplanation. 



The most pronounced effects were secured by hydrating sections 

 of equal parts gelatine and agar, 0.25 mm. in thickness at 14-16° C, 

 which approximated a condition of saturation in ten days with an 

 increase of 2,640 per cent, in thickness and of 2,720 per cent, in 

 volume, the material being highly heterotropic. 



The first renewal of the solution caused a sudden enlargement 

 which in 3 hours added 140 per cent, to the thickness of the sections. 

 The accelerated enlargement following the second change was about 

 120 per cent., the sections coming to rest on the first day in 4 hours 

 and in 3 hours on the second change. The accelerated swelling on 

 the third day amounted to 100 per cent., coming to rest in something 

 over 2 hours, after which a slow shrinkage occurred by which a third 

 of the previously gained amount was lost. The fourth acceleration 

 amounted to 120 per cent, with a subsequent loss of one third this 

 amount in the next twenty-four hours. The fifth reaction gave a 

 swelling of 100 per cent, followed by a loss of half this amount. 

 The sixth reaction gave an increase of 100 per cent, followed by a 

 loss of equal amount. The seventh reaction gave an increase of 90 

 per cent., followed by a loss of 50 per cent. The eighth showed a 

 gain of 80 per cent, and a loss of equal amount ; the ninth a gain of 

 70 per cent, and a loss of equal amount ; the tenth a gain of 60 per 

 cent, and a loss of 60 per cent. ; the eleventh a gain of 80 per cent, 

 and a loss of 60 per cent. The twelfth change gave a gain of 60 

 per cent, and a loss of 50 per cent. ; the thirteenth a balanced loss 

 and gain of 60 per cent., after which the change in both directions 

 became equivalent so that on the sixtieth day the alteration amounted 

 to 40 per cent, of the original thickness, which decreased to 20 per 

 cent, a week later when the observation was closed, 67 days from 

 the beginning. The whole series of reactions in range and intensity 

 might be said to offer a fair parallel to the life of some short-cycle 

 seed-plants, in which any substance or combination of substances 

 which might furnish the basis for the recurrent action might be re- 



