544 APPENDIX. 



use of fatty food ; and the various experiments which were made 

 by him on cats, as well as on men, leave no doubt that the occur- 

 rence of fat in the urine is frequently to be referred to the food. 

 Whether, however, this is the sole cause of the occasional ap- 

 pearance of fat in the urine of healthy animals, appears from the 

 observations which I have made on the urine of tortoises and on 

 the kidneys of the deer (see p. 465 of this volume), to be a matter 

 of considerable doubt. The amount of fat appearing in normal 

 urine is, however, very small, even after a very abundant use of fat, 

 as is shown by the very careful quantitative determinations made by 

 Lang. This observer generally found no more than about O'llg of 

 fat in the solid residue of the urine of cats which had been fed on 

 fatty flesh ; in human urine he found, in one instance, 0'2 in the 

 solid residue. 



I have never observed true milky or chylous urine in which 

 the turbidity and coloration were owing to fat. Urine of this 

 kind owes its peculiarity to an excess of suspended pus-corpuscles, 

 which, in all the cases hitherto observed, originated in the kidneys, 

 and were not owing to vesical catarrh. Whenever* this kind of 

 milky urine is actually found to be rich in fat, it may be owing to 

 the presence of milk added, as in Rayer's case,* for the sake of 

 deceiving the physician. Bence Jonesf has recently examined 

 with care a case of this kind of chylous urine, and the following 

 are the results at which he has arrived : the urine contained from 

 0*7 to 0*8 g- of fat, associated with which there were, however, also 

 albumen, fibrin, and normal blood-corpuscles ; the greatest amount 

 of fat was found in the urine after digestion, although the blood 

 was not found to be richer in fat. 



Neither motion nor rest exerts any influence on the amount of 

 fat in the urine, although it may aifect the above-named abnormal 

 constituents of that secretion. No change could be perceived in 

 the kidneys (on dissection) by the naked eye, and they were not 

 examined by the microscope. 



(53) Addition to p. 427, line 27. We have already spoken, in 

 the first volume, of the amount of sugar in the urine under 

 different physiological and pathological conditions. I must, how- 

 ever, here additionally remark that, contrary to my earlier 

 experiments and the more recent observations of Uhle, sugar 

 occasionally passes into the urine after the use of highly saccharine 



* Traitd des maladies des Reins. T. 1, p. 159. 

 t Philosophical Transactions. 1850, pp. 651-660. 



