ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
347 
reactions whereby proteids are recognized, is not protein, but an iron- 
greening tannin. A number of instances are given where the reaction 
succeeded, in xylem, hard bast, meristem, &c. 
(3) Structure of Tissues. 
Tannin - apparatus of the Leguminosae.* — Dr. P. Baccarini has 
studied the structure and distribution of the tannin receptacles in a large 
number of Leguminosse belonging to all the three sub-orders. They 
are not found in the whole of the order, the Poclalirieae, GenisteeB, 
Trifolieae, and a portion of the Galegese being destitute of them. The 
distribution of the receptacles is very various in the different tribes and 
genera ; the original type may be regarded as that of Ceratonia siliqua 
and Cercis siliquastrum , where they are localized in the epiderm. In 
another type they are hypodermal, and in a third they are immersed in 
the cortex. In those species where there is a tannin-apparatus belong- 
ing to the vascular bundles, it is usually situated in the outer portion of 
the bundle. 
The tannin or tannins are accompanied by abundance of an albuminoid 
substance, and they are by no means confined to these special recep- 
tacles. The receptacles are especially well developed in the Loteae, 
Galegeae, Phaseoleae, and many Hedysareae ; and in these tribes there 
is a clear distinction between an extrafascicular tannin-system and one 
belonging to the vascular bundles (parafascicular) ; one only or both 
systems may occur in the same species. The tanniferous cells are 
characterized by the presence of threads of protoplasm connecting them 
with one another and with the elements of other systems of a different 
histological character. 
Secretory System of Copaifera.f — M. L. Guignard describes in 
detail the system of secretory passages in C. officinalis and other species 
of Copaifera. The structures in which the balsam is formed are found 
in the stem, leaves, and root, but they differ somewhat in the different 
organs. The reservoirs are always of schizogenous origin ; they make 
their appearance in the meristem at an early period. They attain their 
fullest development in the xylem of the stem, where the canals anasto- 
mose into an irregular network. The system differs from ordinary 
secreting canals in the appearance and mode of formation of the border- 
cells. These are not the result of repeated radial divisions of the cells 
which originally surround the cavity, and do not form a distinct layer, 
as is usually the case. They are derived from cambium-cells, the 
number of which varies, but scarcely increases during the formation of 
the cavity. In the root there is at first a single long central cavity in 
the pith ; the number of these subsequently increases, but they remain 
isolated, while anastomosing canals appear in the xylem. In the stem the 
canals of the pith and of the cortex also remain permanently distinct, 
while those of the xylem anastomose abundantly, and usually form a 
circle in the inner part of each zone of growth. In the leaves there is 
a large secreting gland in each mesh formed in the parenchyme by the 
finest veins. 
* Malpighia, vi. (1893) pp. 255-92, 325-56, 537-63 (6 pis.). 
t Bull. rfoc. Bot. France, xxxix. (1892) pp. 233-60 (13 figs.); and Comptes 
Rendus, cxv. (1892) pp. 673-5. 
