Minutes of Proceedings. 117 



early part of the present century that naturalists have learned to 

 recognise, that by a close and attentive study of the lowest and simplest 

 forms of animal and vegetable life could they alone hope to arrive at 

 an accurate idea of the elementary structure of organised tissues, or a 

 knowledge of the processes by which the growth and development 

 of living beings are effected. As the chemist proceeds in his inqui- 

 ries to separate the more complex compounds into their elementary 

 constituents, and then synthetically to reunite those elements into 

 combinations of continually increasing complexity and mass, so the 

 naturalist has learned to seek for the laws of organisation in the 

 simplest forms by which life is manifested, and to study the initial 

 forces of vitality in the properties of the elemental cell. Thereby 

 was that Protean material revealed, not inaptly called the physical 

 basis of life, the protoplasm, coextensive with the organic world, 

 bound up with every vital act, from the lowest organism up to the 

 very highest. For this study the biologist must investigate the struc- 

 ture and functions of unicellular plants and animals ; then he will 

 find that in both great divisions of the organic world the protoplasm 

 is in its essential nature the same, whilst in individual species in both 

 kingdoms it may nevertheless manifest subtle characteristic differ- 

 ences of aspect and behaviour. Being throughout an albuminoid te- 

 nacious semifluid, more or less mobile, it is possessed of an innate 

 irritability ; totally destitute of visible structure, although living ; 

 itself unorganised, it is yet the builder up of all organisation : watched 

 under the microscope in the living state in some of the simplest sarco- 

 dines, this truly marvellous material can be seen altering its outline, 

 sending forth and retracting prolongations of its substance, the so- 

 called pseudopodia, along which the more liquid portions of its mass 

 appear often to ramify and inosculate. Such researches into the 

 problem of life, as manifested by those humble and elemental forms, 

 standing as it were on the threshold of existence, have thrown a 

 wondrous light on many a dark puzzle as to growth and develop- 

 ment. 



The origin of this department of Science is completely modern ; 

 scarcely dating from the middle of the present century. Numerous 

 enthusiastic workers on the Continent and in great Britain have, how- 

 ever, rapidly raised it to its present importance as the basis of philo- 

 sophical biology. The names of Berkeley and Hassall, of Balfs and 



