i LIVERPOOL BIOLOGICAL SOCIETY. 
that is to become tissue must first pass through the 
living state,’ we must provide for growth and renewal 
in the definition, which might stand thus: ‘“‘ Life is the 
consumption and regeneration of protoplasm.’ This is 
not the definition of Dr. Beale, nor do I think it sufficient, 
as it does not bring in the second factor in life considered 
as an action. For be it remembered life is not a static 
state, but a process or action implying continual changes. 
The faculty of undergoing these special changes is vitality, 
but not yet life till the second factor comes into operation 
and takes its part in inducing those special changes in 
which life consists. According to Dr. Beale (Bioplasm, 
p. 60), ‘‘living organisms as well as every particle of 
living matter are incessantly undergoing change* in 
every part, but the rate of change varies marvellously 
in different cases. Some materials passing through the 
stages of living or forming matter, formed matter and 
products of disintegration in a few minutes, while others 
last for many years as formed structure, and perform an 
important office during the whole time.’ There is we 
know a resting and an active stage of living matter, and in 
some forms, as for example the seeds of plants, the 
vitality may be prolonged for an indefinite time with a 
minimum of change, but even in these some small amount 
of change does go on. 
The second factor contributing to those changes is the 
contact with the environment, and this therefore con- 
stitutes an essential part in the process of life. Considered 
in reference to protoplasm, the environment may be 
divided into Pabulum, Conditions and Stimuli. The first 
of these is fully recognised by Dr. Beale, when he says: 
* According to Berthold (Op. cit., 1886, p. 8), ‘‘the protoplasm is in a 
state of continual change, and its composition is being perpetually altered as 
long as life lasts.” 
