14 
TRANSACTIONS OP THE TEXAS ACADEMY OF SCIENCE. 
to be composed; but simply by combining with the complemental mate¬ 
rial so as to restitute its own functionally deteriorated chemical struc¬ 
ture. 
This much being positively ascertained by direct observation, let it be 
clearly borne in mind that living activity, in all stages of development, 
necessitates the direct interaction of these three different and yet indi¬ 
visible functions; first, the functional play with the medium on which 
its vital motion depends; then, on the one hand depurative elimination 
of the waste products of functional disintegration, and on the other hand 
nutritive restitution by means of complemental pabulum. However in¬ 
tricately differentiated into organs, tissues, and components of tissues an 
organism may appear, its structure is out and out the visible substratum 
of this manifoldly related and yet indivisible activity. It is this indis- 
cerptibly correlated threefold disposition of the unitary movement of 
life, that governs organization from its first beginnings to its complex 
development. 
That it is a specific chemical constitution of the living substance, aided 
by its concomitant vital activity, which determines the shape and struc¬ 
ture of an organism, becomes evident when we contemplate the highly 
differentiated substance of such infusoria as, for instance, Stentor, the 
well known trumpet-animalcule. Here, with but very little firmly fixed 
structural organization into tissues, the mostly still fluent protoplasm 
manages to sustain, by dint of its specific chemical construction and 
living motion, the remarkably complex disposition of the differently 
functioning parts of its body. 
The functional differentiation and disposition of the living substance 
is determined by the particular location occupied in the chemical cycle 
of protoplasmic activity. This is directly and distinctly observable in 
higher amoebae; such, namely, as form with their entire substance one 
single process. We have then an ovoid bilateral being, whose shape is 
steadily maintained by out-and-out fluent protoplasm. Its oral pole— 
distinguished from the granular part of the body by being composed of 
hyaline substance—keeps always foremost in space during locomotion. 
This is effected by newly integrated substance constantly flowing out, 
and replacing thereby the functionally disintegrated and shrinking sub¬ 
stance. This foremost part of the body not only plays the role of a 
structurally unformed mouth, by allowing nutritive material, with which 
it comes into contact, to penetrate into the interior, where it forms nutri¬ 
tive corpuscles with what may be termed entodermic substance; but its 
essential function is to carry on, together with the other surface-proto¬ 
plasm the functional play with the medium, the life of outside relations, 
as it is called in higher organisms. Depuration and defecation take, 
visibly, place at the aboral pole. Now mark, all essential functions of 
