INTRODUCTION 47 



life is a series of reactions, integrations and disintegrations. These 

 may be manifestations of life but they are incomplete manifesta- 

 tions and do not tell the whole story. An encysted protozoon, 

 a spore, a seed, a resting egg, or a dried rotifer, shows no more evi- 

 dence of activity than does a parked car, yet each has life and in a 

 proper environment would manifest activity. An emulsion of oil, 

 salts and water manifests activity strikingly similar to the move- 

 ments of an Ameba, yet such an emulsion has no life. The encysted 

 protozoon or the dried rotifer has protoplasmic organization which 

 the oil emulsion has not, and with absorption of oxygen and water 

 becomes animated. Life thus is incontestably bound up with 

 organization of protoplasm and, for descriptive purposes at least, 

 we find a distinct advantage in a clear discrimination between this 

 concept and the concept vitality. Whatever name we give it, 

 however, brings us no nearer to a conception of what life actually is, 

 for it cannot be measured and endures until the organization is 

 disintegrated. With vitality the case is different; here we have to 

 do with protoplasm in motion and the activities can be measured 

 from beginning to end of a life cycle. While organization has evi- 

 dently been continuous from the first protoplasm, vitality has been 

 intermittent or discontinuous. Organization may exist without 

 vitality and has always the potential possibility of vitality, but 

 vitality is impossible without organization. I would define vitality, 

 therefore, as the sum total of actions, reactions and interactions between 

 and amongst the substance* making up the organization of protoplasm 

 and between these and the environment, while life may be defined as 

 protoplasmic organization manifesting vitality or with a potential of 

 vitality. 



