338 THE LUMBAR ENLARGEMENT OF THE SPINAL CORD. 
patience, and objectives of large angular aperture and very clear definition, ranging in 
power from 200 to 700 diameters, are constantly needed to satisfy the observer of the 
truth of what is seen with lower powers. Usually a power of about 120 diameters is 
best calculated for this study, and with this most of my drawings were made; but 
sometimes as high a power as 700 is required for the complete resolution of the 
course of fibres, and none of my drawings were made until the preparation had been 
carefully studied with high objectives. 
Figs. 1, 2, 3, 4, from transverse sections from the anterior cornu, Fig. 5, from a lon- 
gitudinal section through the same cornu, and Figs. 6 and 7, representing respectively 
longitudinal and transverse sections from the posterior cornu, may be referred to as 
exhibiting the different modifications of cell-connection. Sometimes, as at d, Fig. 1, 
the cells are joined by a short, thick fibre; in other cases the process is much longer 
and usually somewhat thinner (Fig. 1, c, and Fig. 2, dd); Figs. 3 and 4 give very 
good examples of both these forms; Fig. 7 shows that these connections are equally 
met with in the posterior cornua, though they are more difficult to make out here, 
owing to the finer nature and more complex arrangement of the fibres. Longitudinal 
sections (Figs. 5 and 6) show chiefly the longer mode of cell-connection ; this is espe- 
cially the case in Fig. 5, from the anterior cornu, where the arrangement of fibres is 
much easier to make out than in the posterior parts of the cord. 
I should, however, state my views very unfairly, did I not urge the great necessity of 
caution in regard to this question of cell-connection. We are able beyond doubt to see 
that some cells are connected together by their processes, but we are at present by no 
means able to state, with Lenhossék, that all the cells are connected in a continuous 
chain; indeed, we have much reason for thinking quite otherwise, the result of a year's. 
observation, principally in this single direction, having convinced me that the un- 
doubted examples of cell-connection, seen even in the most favorable specimens, are 
exceptional rather than constant. In a question bearing on all our ideas of nervous 
conduction so strongly as this does, the necessity for caution in everything like infer- 
ence cannot be too strongly insisted upon. 
(b.) The Connection of the Cells with the Anterior and Posterior Roots. — That fibres 
of the anterior roots have their origin in cells of the anterior cornu has been fully 
established by Bidder, * Schilling, T R. Wagner, t Stilling, § and Schröder van der Kolk, || 
* Bidder and Kupffer, Untersuch. iiber d. Text. d. Riickenmarks, (Leipzig, 1857,) p. 95. 
f De Medulle Spinalis Text. Dorpat, 1852. ; 
i Neurolog. Untersuchungen. $ Neue Untersuchungen. 
|| Op. cit., p. 97. 
