MODEL OF MEDULLATED TRACTS IN BABY's BRAIN 123 



name Him schenkelschlinge. He identifies an ansa peduncularis 

 (fig. 377), an ansa lenticularis and an unterer Thalamus stiel 

 (fig. 220) ; in the brain at birth only one bundle curving around 

 the mesial border of the crus is medullated, namely, the rubro 

 lenticular fasciculus which, I think should be identified with Ober- 

 steiner's ansa peduncularis . 



In connection with Forel's field, Sachs gets a degeneration of 

 Forel's fasciculus from a lesion anterior to the red nucleus and 

 terms the bundle the tractus rubro-globus pallidus which is prob- 

 ably the same as no. 19. He also finds a still more medial bundle, 

 the inferior peduncle of the thalamus, which is entirely non- 

 medullated at birth. It may be added here that the ansa lenti- 

 cularis is also non-medullated at birth. 



The bundle just referred to in connection with the nucleus 

 hypothalamicus of Luys, is not well illustrated in any of the views 

 of the model, since it lies lateral to Forel's fasciculus no. 19 and is 

 nearly hidden by that bundle in the drawings. The hypothalamic 

 nucleus is oval or lens-shaped, both in sagittal section (fig. 8), 

 and in the familiar transverse sections such as are shown in Forel's 

 and von Monakow's figures. It has a capsule of fibers, especially 

 marked at the cerebral end (no. 23, fig. 7). At the lateral border 

 of the Luys' body, the fibres of this capsule cut through the crus, 

 to the globus pallidus. Within the globus pallidus, these fibres 

 lie close to the crus (no. 30, fig. 4) and are distinctly separated 

 from the Forel's rubro-lenticular fasciculus (no. 20, figs. 4 and 7). 

 For this bundle connecting the Luys' body and the globus pallidus, 

 transverse sections are far better than sagittal. This is the bundle 

 referred to by von Monakow as the dor sale A^itheil der Linsenker- 

 schlinge. It shows well in Forel's fig. 12 and von Monakow's fig. 

 26 as the dorsal capsule of Luys' body, lying ventral to the zona 

 incerta and curving through the crus to the globus pallidus. 

 In the model, Luys' body is seen to be connected with the medial 

 lemniscus (no. 11) on the one hand, and with the globus pallidus, 

 on the other hand, by the medullated bundle (nos. 23 and 30) 

 just described. 



To sum up, in the course of the afferent paths to the cortex, as 

 far as they are medullated at birth, there are two great relay 



