810 REPORT— 1901. 



the addition of new molecules to its surface, but the molecules have ah-eady been 

 formed in the solution in which the crystal grows. The molecules are not formed 

 by the crystal ; they are simply added to it by a physical force. But assimilation 

 is a different phenomenon. Like a crystal, living matter grows in a nutritive 

 medium, but the molecules which cause the growth do not already exist in the 

 medium. The living matter does not increase by the addition of molecules 

 already made, but by the creation and absorption of new molecules. Other 

 physiologists have attempted to explain assimilation by osmotic action. But 

 osmosis is a purely physical phenomenon. When a substance traverses an organic 

 membrane, it does not become a new substance. There is no change in its con- 

 stitution. While osmotic action must undoubtedly perform an important role in 

 the phenomena of assimilation, as we see it in all growth, it cannot fully explain 

 it. But if assimilation is an action of a chemical nature, we can suppose that the 

 molecules of the living matter in certain conditions split up and then act on the 

 molecules of the nutritive medium, detaching atomic groups from these molecules 

 and combining with them to form new molecules similar to those of the original 

 living matter, but possibly not absolutely alike. 



Physiologists, however, have often endeavoured to find the cause of assim ilation 

 in morphological structure, the structure of the living substance and of the cell. 

 But when we inquire into its nature we find it to be essentially, one might almost 

 say exclusively, a chemical phenomenon, and a chemical phenomenon cannot be 

 explained by morphological structure. A chemical phenomenon depends on the 

 molecular structure and affinities of the atoms of matter in which the phenomenon 

 occurs. Assimilation is not determined by the physical or structural character of 

 protoplasm, or of the cell, or any part of it, but on the chemical constitution of 

 living matter, that is to say upon the structure of its molecules. This view of 

 the subject has led some thinkers, and notably Ermano Giglio-Tos of Turin, in a 

 remarkable book entitled ' Les Problemes de la Vie,' to form the conception of a 

 biomolecule, or living molecule, that is to say the smallest quantity of living 

 matter that can exhibit some of the chemical phenomena of life, such as respiratory 

 exchange, the function of chlorophyll, the starch-forming function, and functions 

 of disassimilation and secretion. 



Living matter, when examined by the highest powers, presents some of the 

 characters of an emulsion ; that is to say, it is composed of minute particles with 

 fluid matter between them. These minute particles, built up of biomolecules, 

 have been termed by Tos biomones. Biomones, in their turn, form biomonads or 

 bioplasm, or molecular or granular protoplasm, and this again forms the cell. It 

 may be said that these terms are only new names for things that have been long 

 recognised, but it subserves clear thinking to decide upon common terms which all 

 may use. The cell theory undoubtedly has served its day, but it is remarkable 

 that as cytology progresses the physiological importance of ditferent parts of the 

 cell seems to diminish, and it is necessary to give to the constitution of living 

 matter a much wider and more general explanation. The conception of abiomone, 

 that is a minute particle, showing the chemical phenomena of life, enables one to 

 understand how vital phenomena may be manifested without, for example, the 

 existence of a nucleus. The granules in protoplasm, or, as Tos terms them, 

 biomonads, are built up of biomones — and one can conceive that the little colony is 

 symbiotic ; that is to say that each part is necessary, and each part co-operates with 

 the rest. But when we come to the ultimate analysis, the distinctive character 

 of different kinds of protoplasm, or cytoplasm, or archoplasm, or corpuscles — call 

 the material by any name the most convenient and expressive, depends on the 

 chemical nature of the substance. 



These remarks are all in the direction of showing that as research progresses, 

 and as we get a deeper insight, we find that the phenomena of life are never found 

 in structureless matter. It may appear to be morphologically structureless, even 

 to the highest powers, but in a molecular sense it is structural. The progress of 

 histology also points in the same direction. How often, in former years, were 

 we in the habit of describing appearances in tissues as structureless or ' finely 

 molecular,' which we now know, by better methods shows numerous details of 



