pointing to the probability that there are certain nerve fibres which do not depend on the ganglion for their trophic supply, but derive the same from elsewhere, either the spinal cord at another level, or the periphery.

In conclusion, the author calls special attention to the value of the method of excluding one or more nerve roots during an epileptic spasm, as affording a means of confirming the facts that have been previously observed from stimulation of the nerve roots, and also of ascertaining new facts with regard to them and the plexuses which they form. He further goes on to point out that it supplies a valuable means of studying the manner in which conduction of impulses from the cortex through the nerve roots and plexuses to the muscles takes place; and that it is capable of still wider extension, as if, instead of producing general epilepsy, less powerful stimuli be applied to the centres for different movements, as represented in the motor cortex, it will afford a means of connecting such centres, or parts of these, with the nerve roots to which fibres proceed from these cortical motor

centres.

III."The Influence of the Kidney on Metabolism." By J. ROSE BRADFORD, M.D., D.Sc., Fellow of University College, London, Assistant Professor of Clinical Medicine at University College, Grocer Research Scholar. Communicated by Professor SCHÄFER, F.R.S. Received February 18, 1892.

(From the Physiological Laboratory of University College, London.)

The results described in this preliminary communication were obtained in a series of experiments commenced in June, 1889, and at present still in progress, with the object of elucidating the functions. of the kidneys, and to gain an insight into the disturbance produced in the economy by disease of these organs.

Method. All the experiments were made on dogs, and a complete experiment involves the following stages :

Firstly. The animal, after being weighed, is placed in a suitable chamber, and fed on a weighed diet containing a known quantity of nitrogen; the water drunk is also measured. The amount of urine passed is measured, and the quantity of urea and total nitrogen in it determined. Finally, the weight of the fæces and the amount of nitrogen in them are also determined. All the nitrogen determinations were made by means of Kjeldahl's method; the urea was estimated by the hypobromite method. A daily determination of the above factors was made for a period of a week, and a daily average

thus obtained. In the earlier experiments only the quantities of urine and urea passed were determined. On removal from the chamber, the animal is again weighed.

Secondly. The operation described below is performed on one kidney. After recovery from this, the dog is again placed in the collecting chamber, and the above data again obtained for a week or more.

Thirdly. The second kidney is removed, and the animal again placed in the collecting chamber, the food and excreta being again determined for a period of a week or more.

Fourthly.-At a variable time after the second operation the animal is killed by bleeding, and the amount of nitrogenous extractives present in the tissues determined.

As regards the operative procedures, there is nothing to remark about the second operation-the kidney is removed in the usual manner by lumbar incision; a few words are necessary in order to describe the first operation. After anesthetising the animal with chloroform and morphia, the kidney is exposed by a lumbar incision and freed from its connexions. The vessels in the hilus are then compressed with the fingers, the kidney transfixed from before back, and a large wedge of kidney substance, with the apex of the wedge at the pelvis of the kidney, removed from the middle of the organ. The piece removed weighed from 5 to 15 grams in different cases. The very free hæmorrhage is arrested by ligature of the large vessels divided, and by pressure on the cut surface. When all bleeding had been arrested (the vessels in the hilus being of course no longer compressed) the cut surfaces of the kidney were brought together by two or three silk sutures passed in deeply, and by numerous superficial fine horsehair sutures involving only the cortex and capsule of the organ. The abdominal wound was closed and dressed in the usual

manner.

Full antiseptic precautions were always used, and morphia was given hypodermically to prolong the narcosis.

Summary of Experiments.-Twenty-three animals survived the first operation fifteen animals survived both operations.

Thus, eight animals died after the first operation and before the second. The causes of death in these eight were as follows:

In four cases the animals were accidentally killed with chloroform administered to perform the second operation. In two cases the wound became septic and the animals were killed. In one case death resulted from hæmorrhage on the seventh day, and one dog, to which further reference will be made below, died of asthenia thirty-six days after the first operation.

This communication deals with the results obtained in the fifteen complete experiments. In one, the first, no observations were made on the urine, and in three dogs the observations were incomplete, so

that there remain eleven cases in which observations were made on the urine before and after the operations.

Effects of the First Operation (i.e., the removal of a wedge of the kidney substance).-The shock of the operation passes off in about twenty-four hours, but for two or three days there is some hæmaturia, and the appetite is poor. The temperature of the body remains at its normal height, or there may be slight pyrexia. The dog, however, soon regains its former health, and no permanent ill effects result from the operation in the great majority of cases. In one case (one of the eight incomplete experiments) the animal died thirty-six days after the operation, with considerable wasting and loss of appetite, and nothing was found post mortem except extreme atrophy of the kidney operated on. The opposite kidney was healthy and of normal size. The atrophy was very marked, as the following numbers show:-7.6 grams of the left kidney were removed, post mortem the remaining fragment of the left kidney weighed only 3.5 grams, and the opposite kidney 18 grams. In this case, the only one where death resulted from the effects of the first operation, although the atrophy was very marked, there was microscopically no evidence of cirrhosis, and no lesions of the renal vessels were discovered. The cause of death is obscure, as the second kidney was not removed.

With this one exception, the first operation failed to produce any serious or permanent ill effects, and the only result noticed was slight emaciation, but this was generally recovered from in a week or two.

A period of from one to six weeks was allowed to elapse between the first and second operations, and during this time the animal was placed in the chamber, and the ingesta and excreta determined. The following table gives the results observed in five cases :—

From this tabular statement of the results in five cases it will be seen that, as stated above, the results of the operation are trifling when we consider its severity. In one case, No. 16, the output of urea was increased from 7 to 10 grams per diem. In this case the ingesta were not determined, and the apparent increase may have been due to an increased diet. In No. 22 the diet was the same before and after the operation, but there is an increase in the urine and urea after the operation. This case is quoted because it illustrates the maximum effect produced; in no other case was so great an effect observed. In the other cases the effects on the urine, &c., are so slight as to be well within the limits of experimental errors. The loss in body weight is trifling when compared with that described below as resulting from the second operation. The greatest loss observed was in Dog 22, where the body weight fell from 14 lbs. to 12 lbs. The specific gravity of the urine is not permanently affected by the operation. In the first few days after the operation, whilst there is hæmaturia, the urine is frequently more abundant in quantity and the specific gravity then is temporarily lowered, but this soon. passes off, and the urine returns to its normal quantity and density.

The Results following the Second Operation.

The results following the removal of the second kidney differ widely from those described above as following the first operation, in that there are frequently no immediate ill effects, the animal running about, &c., within a few hours of the nephrectomy, and there is but little shock, hæmorrhage, &c., when compared with the first operation. The remote effects, however, are very marked: a widespread disturbance of nutrition ensues, accompanied by extreme wasting, hydruria, and polyuria, and with these a fall in the body temperature and a great increase in the nitrogenous extractions of the tissues, provided a sufficiently large amount of kidney has been removed at the first operation.

In all cases the wound has healed up rapidly and soundly, and in no case has death resulted directly from the operation. Out of the fifteen experiments, the first was killed five days after the second operation, and at that time the animal was in sound health. In four cases, No. 2, No. 11, No. 19, and No. 21, the animals were killed 47 days, 60 days, 14 days, and 30 days respectively after the second operation, and the results observed in them will be described below (vide Table IV). In the remaining ten cases the dogs either died of a rapidly progressive asthenia, or else they were killed at a time when they were practically moribund.

The results in four cases out of the ten are given in the following table: