ME. J. L. CLAEKE ON THE INTIMATE STEUCTUEE OE THE EEAIN. 
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of gold and potassium to 10,000 parts of water slightly acidulated either with vinegar 
or hydrochloric acid, for ten or twelve hours, when the white substance becomes of a 
pale lilac (blass lilla), while the grey substance is scarcely coloured. They are then 
placed in a mixture of 1 part of hydrochloric acid to 2000 or 3000 parts of water for a 
few minutes. After this the sections are steeped for about ten minutes in a mixture of 
1 part of hydrochloric acid to 1000 parts of 60 per cent, alcohol, and then for some 
minutes in absolute alcohol ; after which they are made transparent by means of creo- 
sote and put up in Canada balsam*. This is rather a complicated process. 
Explanation op the Plates. 
PLATE VIII. 
Fig. 1. Transverse section of the lower end of the human medulla oblongata at the points 
of the anterior pyramids : — b c, the posterior column ; d, the posterior part of 
the antero-lateral column ; e, the caput cornu posterioris, or expanded extre- 
mity of the posterior horn ; d', network of fibres and blood-vessels, mixed with 
small nerve-cells, in the deep portion of the lateral column, between the ante- 
rior and posterior horns ; t, central grey substance behind the canal ; in front 
of the canal is seen the commencing decussation of the anterior pyramids ; 
z, the anterior median fissure. 
Fig. 2. A similar section a little higher up. The decussating fibres of the anterior 
pyramids are much more numerous : V is a portion of the anterior column 
of the spinal cord forming the non-decussating part of the anterior pyramid 
of the same side. 
Fig. 3. The same, a few sections higher up : — -f, d', d', bundles of fibres coming from the 
lateral column and lateral grey substance to form the anterior pyramid of the 
opposite side ; b, V, rudiments of the posterior pyramid. 
Fig. 4. The same, still higher up : — -f, anterior cornu ; o, conical eminence from the 
outer part of the cervix cornu forming the rudiment of the grey nucleus of 
the restiform body ; b , b, posterior pyramids containing grey substance derived 
from the inner part of the cervix cornu on each side of the posterior median 
fissure. 
Fig. 5. Similar section at the upper part of the decussation of the anterior pyramids : — 
b', grey nucleus of posterior pyramid very much enlarged ; e, caput cornu 
posterioris (grey tubercle of Kolando), also greatly enlarged ; o, inner grey 
nucleus of restiform body much increased in size ; c', its outer grey nucleus ; 
1c, posterior median fissure ; t, rudiment of central spinal-accessory nucleus ; 
t\ rudiment of hypoglossal nucleus ; f, remains of anterior cornu of spinal 
cord ; n", bundles of fibres coming from the restiform nucleus (o) and from 
* Zur Anatomie des Menschl. Eiickenmarks. Medecin. Centralbl. Nos. 24, 25. 
