156 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



to Latham* active living plasma consists of a chain of 

 cyan alcohols united to a benzene nucleus and thus 

 forming a body which is extremely unstable and very 

 prone to molecular change. From this substance, by 

 dissociation and re-arrangement, the various metabolic 

 products of protoplasm can be derived. On drying, a 

 re-arrangement of the protoplasmic molecule into a stable 

 grouping, which may or may not be accompanied by 

 dissociation, takes place. On the addition of water an 

 extremely rapid re-combination and re-organization occurs, 

 the unstable active living protoplasmic molecule being 

 again produced and almost immediately commencing to 

 respire and assimilate. The protoplasm of a plant, which 

 is unable to withstand dessication, is probably resolved on 

 drying into a stable series of substances from which, inter 

 se, no re-organization of the protoplasmic molecule can 

 take place. It is interesting to notice that no cell, the 

 protoplasm of which shows streaming or rotation, can 

 withstand dessication. It appears that where the vital 

 activity of the plasma manifests itself in the form of 

 rotation or circulation, the preservation of vitality is 

 indissolubly connected with the presence of free fluid 

 water in the protoplasm. 



A cell is resistant to drying, when its protoplasm is 

 readily stimulated by the loss of water to re-arrange its 

 molecular grouping in a stable, and hence resistant mole- 

 cular arrangement and one from which, at the same time, 

 a re-awakening is possible. The re-awakening is normally 

 very rapid and does not involve any appreciable latent 

 period but in other cases a more or less prolonged latent 

 period seems to intervene between the absorption of 

 water and the complete resumption of vitality as evidenced 

 by the return of respiration and assimilation. Here it is 

 * Latham. Brit. Med. Journal, Vol. I., 1886, p. 629. 



