841 in the muscles below the knees. The case resembled very closely Kocher's case No. 70, recorded on p. 633 of his work, "Die Verletzungen der Wirbelsilule." Remarks by Mr. MOYNIHAN.-In attempting to unravel and elucidate the problems of central nerve lesions and their peripheral expression we are met at the outset by certain irregularities, certain individual variations which are almost bewildering. A good deal of mental trouble will be saved to the student if he remembers the anatomy of the

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... acral and lumbar plexuses. Unfortunately, these are, anatomically speaking, too often considered as separate plexuses, when, as a matter of fact, they are one and indivisible. The key to the arrangement of the lumbo-sacral plexus is the " twopronged" nerve (the" nervus furcalis" of von Jhering), normally the fourth lumbar. In some cases this nerve enters largely into the lumbar plexus, in other examples almost the whole of it goes to join the sacral plexus. The proportion of it that joins the sacral plexus has been shown by Eisler to vary from one-twentieth to eighteen-twentieths. It is obvious therefore that the distal expressions of a central lesion occupying an identical position in two cases may vary within very considerable limits. The case recorded here is especially interesting in the fact that the results of the lesions are not symmetrical. On the left side the anterior tibial muscle, the peronei and the calf muscles have wholly lost their function, whereas on the right side the wasting is much less marked and there is a certain, though almost insignificant, amount of reaction in the gluteus maximus and the anterior tibial and peronei muscles. The difference in the two sides is very well shown in Fig. 2 . On the left side FIG. 2. Illustration of legs showing amount of wasting and paralytic club foot. the area of anaesthesia extends decidedly higher than on the right side, reaching almost to the level of the knee-joint (vide Fig. 1 ). The most feasible explanation, I think, is this: the second, the third, and the fourth sacral nerves are destroyed on both sides and I believe the first sacral nerve is also. I think that the fifth lumbar on the right side is free and it seems not improbable that the area assigned by Kocher to the first sacral (including the kidney-shaped area in the sole) may be supplied by the fifth lumbar. (Kocher gives no peripheral cutaneous area to the fifth lumbar.) On the left side the fifth lumbar and a portion of the fourth lumbar are destroyed. This would account for the higher level of anaesthesia and for the muscular palsy. Paterson has shown that for his cases at any rate the following innervation held good: gastrocnemius, 5 L., 1 and 2 S. ; soleus, 5 L., 1 and 2 S.; anterior tibial group, 4 and 5 L., 1 S. ; peronei (longus et brevis), 4 and 5 L., 1 S. If, as I assume, the fourth lumbar partly and the fifth lumbar wholly are destroyed on the left side, the exact muscular wasting is produced which can be explained by Paterson's investigations. Kocher gives the muscular innervation as follows: gastrocnemius and soleus, 2 and 3 S. ; anterior tibial and peronei, 1 S. If, therefore, we assume that the cutaneous areas of Kocher are correct, his muscular allotment of nerve-supply must be wrong, and vice versic. Both cannot be right. However, one cannot argue from an isolated case. The conditions in this case are extremely interesting and afford an enticing subject for discussion.