JULY — SEPT. 1857.] helween the Animal and Plant, 179 
endesmose the elements of nutrition, which thus pass in their crude 
state into the general circulation, where they are elaborated and 
fitted for their future destiny. In the vertebrate animal, the lac- 
teals already referred to terminate by looped extremities amongst 
a number of cells and nuclei ; and during the passage of chyme 
along the intestine these nuclei become developed into cells, and 
the cells are busy at work selecting, absorbing and elaborating, and 
then yielding up their contents to the loops of the lacteals. In 
plants the root is the great (jrgan of absorption, whether suspend- 
ed in air, floating in water or buried in the earth. The root con- 
sists of a cellula^epidermis, and internal structure of vascular bun- 
dles and cells. H^re then cells are still the great organs of ab- 
sorption, and if we trace the sap upwards through the alburnum and 
leaves, and its return through the lactiferous vessels and cells of 
the bark, we shall find them not less active and essential in the 
process of assimilation. If we now review the function of respira- 
tion in the animal and plant, we shall find that although by this 
process the animal eliminates carbon and consumes oxygen, while 
the plant fixes the former and gives off the latter, being thus so far 
opposed in object, they nevertheless agree inasmuch as respiration 
is carried on in both kingdoms, by means of organs of a cellular 
structure. In both too the ultimate objects of the function are the 
alteration and refinement of the circulating or nutritious fluid, the 
blood in the one and the sap in the other being fitted for the pro- 
duction of new or repair of old tissues, and for keeping up a sup- 
ply of the various secretions. Respiration is therefore a depura- 
tory process, and perhaps the least vital of any of the functions of 
organic life, many of the changes it effects being merely the results 
of a chemical action. We come now to speak of secretion, which 
is carried on by means of certain cellular organs called glands. 
These appropriate each a definite nature of material from the cir- 
culating fluid, as it passes along fertilized by the results of absorp- 
tion and assimilation. Besides their nutritious elemente however, 
the blood and sap contain unorganizable substances the effete pro- 
ducts of tear and wear, which are separated to be excreted by 
glands differing in no important particulars from those already 
mentioned. The individual cells concerned in the manufacture of 
