56 



CARNEGIE INSTITUTION OF WASHINGTON. 



lessened swelling in thickness and increased swelling parallel to the 

 broad surfaces of the plates. The relative increase in length and 

 width of sections of old plates was double that in the same plates 

 when newly made and swelled in water. Similar increases occurred 

 when old plates were hydrated in chlorides of K, Na, Mg, and Ca at 

 O.OOOlM. 



The effects of age on gelatine plates are not so marked, but the 

 areal swelling increases with age. The differential effects of the 

 various solutions on such areal or linear increases were very marked 

 and noticeable. Thus, strips 30 to 50 mm. in length cut from a 

 single plate when placed in the solutions gave increases in thickness 

 and length as below : 



The areal increase in the potassium solution varied but little in 

 the different concentrations, being much greater than in the calcium, 

 which was near that in water. The greatest disproportion, however, 

 between increase in thickness and in length was in the acid. 



Agar was made into plates with an inclusion of minute proportions 

 of chlorides of calcium, potassium, and magnesium which would 

 represent possibilities in the plant-cell. When such salted plates 

 were hydrated in solutions of KCl, NaCl, and HCl at 0.0001m, the 

 swelling in length amounted to 12 to 14 per cent, as compared with 

 increases of 3 to 4 per cent which might be shown by pure agar. 



Equally interesting results were obtained with salted gelatine. 

 Among the more important effects it is to be seen that the increase in 

 length of therotropic plates is lessened by the incorporation of salts 

 when swelled in KCl. The presence of incorporated salts accelerates 

 increases in length in CaCU in an uncertain manner, but exercises 

 such an effect rising with the concentration in acid. The presence of 

 incorporated salts lessens the increase in length in KCl, does not 

 modify it greatly in HCl, but exaggerates the increase in CaCl2 at 

 0.01m. 



The significance of the above data lies in the fact that living matter 

 and the structures in the cell, to which so much importance in heredity 

 and physiology is attributed, are bodies in a similar colloidal state. 



