OF FORCE. 
195 
of lime in the paste; septaria in argillaceous rocks is an example which is quite common 
in formations of this kind. These concretions are formed there by molecular attraction : 
it differs from chemical, inasmuch as the new mass is composed of one material, and 
without having undergone a change, except change of place. 
Molecular force can not be regarded as a force which is influential in producing changes 
in organic bodies : this is prevented by the activities of the other forces; when, however, 
these are diminished, when the force of circulation is diminished by age, concretions of 
carbonate of lime are found about the large blood vessels and valves of the heart, which 
operate mechanically in deranging the movements of the apparatus. But these are acci¬ 
dents in the animal economy. Something similar to this takes place in vegetables when 
crystals are formed in the cellular tissue, the bark for instance. These crystals are called 
raphides by botanists, and are generated in the fluids, and finally crystallize out: they are 
quite insoluble, and hence remain unaffected by liquids which surround them. In this 
case, as in the concretion of lime in the vessels about the heart of aged persons, the crystals 
are foreign bodies, and have nothing to do with- the functions of the plant. Molecular 
force is one of the general forces of inorganic matter, and must be coextensive with gravi¬ 
tation. It differs from cohesion. As a common product of many vegetables, it would 
seem that the formation of starch is the nearest approach to molecular force : but it is 
scarcely to be regarded as its product, inasmuch as it is still within the reach of the other 
forces of the plant, and may be transformed into wax and sugar; it is not, therefore, a 
crystallization like the raphides, nor a concretion like Septaria in mud deposits ; it is a true 
secretion, and remains within the influence of the special forces of the plant. 
The forces which are active in plants and animals may be said to reside in the cells ; each 
cell is an organ, and in one view it may also be said to be an individual, as it performs all 
the functions of an individual; the materials which are changed come in contact only with 
the cell, and it is within this little organ that great results are brought about. 
A single cell then produces gum or a grain of starch, not the compound organ, but the 
individual cell. A grain of wheat has no force in itself to form starch or gluten ; a cell is 
first formed, and if the gluten and starch, and gum were dissolved out, the shape of the 
kernel would remain, and the kernel would be found to consist of many empty cells. The 
kernel or grain has no force which can produce starch : it would be assuming the existence 
of a force anterior to the existence of the being exercising it. The kind of force in opera¬ 
tion in the tissues of plants and organs of animals is inferred from the phenomena we wit¬ 
ness ; and in all cases where the phenomena are different we have a right to infer a dif¬ 
ference in the antecedent form : we have no other means of determining the nature of 
the forces. A magnet moves a bar of iron ; sulphuric acid and ammonia combine ; mole¬ 
cules of carbonate of lime, when diffused through a paste of other materials, unite and 
form masses: we give the first as a magnetic force, the second as a chemical force, and the 
third as a molecular force. Water rises in tubes when the bore is extremely small; it is 
called capillary attraction. Each example is characterized by peculiar phenomena, and 
