IN the interesting paper on the fourth cranial nerve by MIr.Parsons in the December, 1921, number of this Journal there are three points that seem to need a little criticism. In a reply to a private communication from myself he has kindly asked me to write a paper on that nerve. I hope to show here :-(1) That the decussation of the fourth nerve is not quite complete; in short, that it contains a few uncrossed fibres; (2) that the sixth nerve nucleus gives origin to uncrossed fibres exclusively, all of which pass out in the homolateral sixth nerve; and (3) that the mesencephalic trigeminal root is not motor, and cannot therefore form the visceral motor component of the fourth cranial nerve. It so happens that a few years ago I wrote two papers(22) which dealt rather full-with all these matters; so I shall give here merely the salient points of those papers. The title of the earlier paper (1910) was: _" The mesencephalic fifth root; the dorsal glosso-pharyngeal nucleus; and the question of an endo-netural afferent ganglionic system." The title of the second paper (1913) was :--" Direct trochlear and crossed oculomotor fibres." I will begin now with the mesencephalic fifth root.The mesencephalic trigeminal root is of extreme antiquity; it is present and has the same relations in a 13 mm. embryo of the very, ancient selachian squalus acanthias as it has in adtult man.

A progestogen (norethisterone) and a dopamine antagonist (sulpiride) were given alone and in combination to volunteers to examine their effects on excretion of ovarian steroids. Compared with non-treatment cycles (n= 15), contraception with a progestogen alone (n= 10) was associated with increased excretion of oestrone and partial suppression of excretion of pregnanediol, suggesting partial luteinisation of unruptured follicles. By contrast, the combination of norethisterone and sulpiride (n=9) suppressed both ovarian steroids to basal values, the suppression being even greater than with sulpiride alone (n=5).These results suggest that a combination ofa progestogen with a dopamine antagonist might have a role in contraception.

AFFERENT FIBRES IN VENTRAL SPINAL ROOTS. [MTHIC RITsL 359 now. One can but marvel how the surgeons of a century ago managed to perform the operations and secure the results they did.

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