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ELEMENTS OF MATERIA MEDICA.

3 . Peculiarities of Actions or Functions.

Inorganized Bodies.

1 Are produced by the agency of co-hesion and affinity, at the expense ofother previously existing bodies.

2. Are preserved or exist solely bycohesion and affinity.

3. Are in a state of rest.

4. Undergo no alterations in their na-ture, except such as result from the opera-tion of attraction and repulsion.

5. Have active properties which arealways the same in degree and kind.

6. Have an existence which is not ne-cessarily limited or definite.

7. Perform actions rcferrible to repul'sion and attraction only.

Organized Bodies.

1. Are produced by other similarly con-stituted bodies, which we call parents. )There are, indeed, many cases in whichwe cannot demonstrate the existence of aparent; and several arguments may beadduced in support of the doctrine ofequivocal generation ; but the majority ofphysiologists are opposed to it, and adopt

as an axiom the statement of Harvey,

“ Omne vivurn ex ovo." Cohesion andaffinity are insufficient to account for theproduction of organized beings, and hencewe call to our aid another power, whichwe denominate “ the vital force.”

2. Are preserved or exist frequentlyin opposition to the usual operation ofcohesion and affinity by the agency of“ the vital force.”

3. Are in a continual state of activity,

taking in from the external world certainsolid, liquid, and gaseous substances, as- .similating them to their own proper .fluids, and converting them into solids, or jpreparing peculiar liquids from them. |These phenomena constitute the process «called nutrition. |

4. Are incessantly undergoing changes, jso that at different periods of their exis- Jtence their properties are somewhat dif- |ferent. Thus they increase, become de- Jveloped, arrive at maturity, and, lastly, . jjdecrease. The phenomena of age , there- |fore, are peculiar to organized beings. ?

->. Have active properties which vary in <degree and kind: the distinction of health fand disease which depends on this variationis, therefore,peculiar to organized beings. '

6. Exist only for a limited period. The ;cessation of their existence is denominated jdeath. The oldest organized beings on ourplanet are probably t heBaobab trees (Adan-sonia digitata) described by Adanson ; theages of some of which have been computed

to he five or six thousand years! Thoughthere is, perhaps, great exaggeration inthis calculation, yet these trees are un-doubtedly very aged.

7. Present phenomena which cannot beexplained by reference to attraction andrepulsion merely: we, therefore, admitother properties, called vital, which werefer to life, or the vital force.