xxiv NUTRITION OF THE TEXTURES. 



majority of organic beings it assumes the form of a nucleated cell (protoplast, or 

 monoplast), as the first condition of their organised structure, in simpler modes of life 

 and organisation it is not subject to the same limitation of form and mass. In the 

 mycetozoa (myxomycetes), a curious tribe, heretofore mostly reckoned among the 

 fungi, but standing as it were in the debateable ground between the animal and 

 vegetable kingdoms, the protoplasm is extended into reticular masses, or irregularly 

 anastomosing trains, spread over the surface of bark and other bodies to which it 

 parasitically clings ; whilst in vibrios and some other infusorial animalcules of the 

 simplest kind, it appears as fine molecular particles ; but it is most probably derived 

 from parents in all instances, however minute and apparently insignificant these 

 may be. 



Professor Beale proposes to distinguish the matter of organised bodies into two kinds, 

 viz., " germinal matter " which comprehends the active matter of cells and nuclei, 

 and appears to correspond with what has been already described as protoplasm and 

 " formed material," under which term he includes all the structural elements and 

 intercellular substances lying outside and between cells, the cell-wall itself when 

 present, and certain products, not germinative, which may be included in the cell- 

 contents. " Germinal matter " grows and increases, and is converted into " formed 

 material;" and all " formed material" has passed through the condition of " germinal 

 matter." In nutrition, according to Dr. Beale, " pabulum does not pass through the 

 cell- wall to become altered by the action of the cell, but certain of its constituents are 

 converted into germinal matter, the living substance, which becomes tissue, or is 

 changed into substances which form the constituents of the secretions." Formed 

 material may be endowed with peculiar and important properties, but is destitute of 

 the power of producing matter like itself, "it has no power to produce structure or to 

 alter itself." * I presume it is not meant by this to imply that " formed material " is 

 incapable of undergoing further organisation ; for otherwise the proposition would be 

 in contradiction to well-known facts, such as the formation of fibres in the matrix of 

 cartilage, &c. 



Professor Bennett considers that organisation begins with molecules or granules of 

 various composition and endowments. These are of two kinds histogenetic, formed 

 by precipitation from fluids, &nd.histolytic, derived from the disintegration of previously 

 formed tissues. Molecules of disintegration may in peculiar circumstances become 

 the basis of matter which undergoes development, so that histolytic or disintegration 

 particles of one period become the histogenetic or formation molecules of another. 

 Certain molecules are endowed with the power of active movement, and the motions 

 in cells and tissues depend upon them ; they are mutually attracted by a molecular 

 force, and thus unite to produce cells and higher forms of tissue. t 



Molecules and granules are, no doubt, more elementary forms of organisable 

 substance than cells ; still it is matter of observation that in the early embryo and in 

 the production of certain tissues, these particles in the first instance unite to form 

 cells. This, Dr. Bennett by no means denies, only he regards the formation of cells 

 as of subordinate moment in the general process of organisation. For my own part 

 I am disposed to think that in the process of organisation, as distinguished from its 

 result, the cognisable form and mass of the organisable material, whether as cell or 

 molecule, are of altogether subordinate consideration to the nature of its substance. 



NUTRITION AND REGENERATION OF THE TEXTURES. 



Nutrition. The tissues and organs of the animal body, when once em- 

 ployed in the exercise of their functions, are subject to continual loss of 

 material, which is restored by nutrition. This waste or consumption of 

 matter, with which, so to speak, the use of a part is attended, takes place 

 in different modes and degrees in different structures. In the cuticular 



* On the Structure of the Simple Tissues of the Human Body, &c., 1861 ; and Archives 

 of Medicine for 1862. 



f For a brief but lucid exposition of his views on this subject, see Dr. Bennett's paper 

 On the Molecular Theory of Organisation, as given in abstract in the Proceedings of the 

 Royal Society of Edinburgh for the 1st of April, 1861. 



