CELLULAR TISSUE. 



the Pleurothallis ruscifolia. 



This resemblance between animal and vegetable structures is equally well seen in 

 the tissue of 

 the egg - shell 

 (Fig. 31), when 

 contrasted with 

 the elongated 

 cells of the Bo- 

 letus (Fig. 25). 

 It is an evi- 

 dence of the 

 power and wis- 



Fig. 44. Cells of fibro-cellular tissue dom'of the De- 

 in situ, A, in the leaf of an ORCHIS, 

 ~* " -"- ity that all the 



tissues, both in 



animals and plants, are produced from one simple 



structure the fundamental cell. 



The uses of the cellular tissue are : 

 1st. To contain various important secretions, as 

 that of starch, and the organs of reproduction in all 

 classes of plants. 



2nd. To carry on the circulation more or less in 

 all plants, but more particularly in those which con- 

 Fig. 46.-Cartilage from the sist only of this tissue. This is well exemplified in 

 ear of the rat, closely re- fa e i ea f O f the Vattisneria (Fig. 47), in which the 

 sembling loose cellular , ,. , ,, 



tissue in vegetables. circulation may be seen proceeding under the 



microscope. 1 



Fig. 45. Fat cells in animals. 



Fig. 47. Leaf of an aquatic plant, the VALLISNERIA SPIRALIS, showing the circulation in plants. 



1 represents the leaf after the upper surface has been sliced off, and shows at B the cellular tissue, 



with small rounded grains, chiefly composed of starch, and a larger detached body the nucleus. 

 The portion at C is a bundle of woody fibre, in which the circulation is also proceeding. The 

 circulation proceeds around each cell separately, and the arrows indicate its direction along the 

 bottom of each cell. 



2 has been drawn from the surface of the leaf, and shows a number of starch granules in cells 



chiefly aggregated together, and which do net circulate. Magnified two hundred diameters. 



