40 M. L. Garreau on the Functions of 



branous matter of the nucleus, arise from the periphery of this 

 organ, and present the greatest variety in size ; but from the 

 vital activity in them, and their consequent variability, it is diffi- 

 cult to determine their individual dimensions. Thus, there are 

 some whose diameter is for the moment equal in width to half 

 that of the nucleus, whilst others do not reach the twentieth or 

 thirtieth part of the diameter of that organ. Their number varies 

 equally with their dimensions : at one time a dozen may be seen 

 in the epidermic cells of Tradescantia virginica, from six to eight 

 in the epidermis of the flowers of Lupinus albm, oiHelleborus niger, 

 and of Lilium album, in the leaves of Crassula, in the epidermis 

 and cellular network under the epidermis of the leaves of Aspho- 

 delus luteus, in the hairs of the young merithalli of Lamium 

 and of Geraniums, &c. Lastly, a certain number always escape 

 observation, inasmuch as they cannot be all brought at once 

 within the focus of the lens, and because during the time of ex- 

 amination changes take place among them, both in respect to their 

 relations and dimensions, and create an obstacle to the definite 

 distinction of one from another. 



Ordinarily these canals radiate from the nucleus towards the 

 periphery to reach the inner wall of the cell. In this course, 

 some decrease in calibre but slightly, others traverse the 

 distance with uniform width, and almost all frequently anasto- 

 mose together, either directly or by the medium of lateral offsets 

 they may give off. By this arrangement a network is produced 

 which varies in character in each cell, and is at one time sus- 

 pended within the cavity of the cell, at another partially 

 attached to the cell-wall. It also happens that at those points 

 where the canals anastomose there is an enlargement, which in 

 its appearance resembles a nucleus additional to the true one, 

 or, in other words, it becomes a centre to and from which a cer- 

 tain number of currents converge or diverge. Before following 

 these canals to their distribution on the cell-walls, we will recall 

 some of their principal physical and chemical characters. They 

 present themselves under the aspect of thin extensile filaments of 

 very great transparency; their component matter has the ap- 

 pearance of a viscid mucus, and seems not to differ, except by 

 its greater consistence, from that which constitutes the small 

 floating flocculi which are observed in circulating or rotatory 

 motion in the young cells of Nitella flexilis and of Chara, in the 

 cells of the hairs of Hydrocharis morsus-rance, and in those of the 

 petiole of Sagittat-ia sagittifolia, &c. The observer unskilled in 

 the investigation of these canals experiences some difficulty in 

 discovering them, by reason of their great transparency, and 

 especially when they are sought for in tissues much loaded 

 with water, where their refracting power differs little from that 



