jSTovember 24j 1905.] 



SCIENCE. 



659 



bibasie wotild act more strongly than the 

 monobasic salts. Comparative study of the 

 action of Glauber salt and common salt in- 

 jected into the blood vessels, made by Dr. 

 Halsey, yielded the expected results. Re- 

 sults similar to these unpublished ones, 

 have been obtained by Gottlieb and Mag- 

 nus of Heidelberg, and especially by 

 Cushny, of Ann Arbor. The isosmotic 

 solution of Glauber salts possessed a much 

 more strongly diuretic action than common 

 salt. From these experiments we may con- 

 clude with Cushny that the salts prevent 

 water resorption from the tubules and set 

 up a kind of diarrheea in proportion to 

 their power of withdrawing water, and that 

 hence in accordance with the Ludwig the- 

 ory, we must assume that a resorption of 

 water occurs under normal conditions. 

 The matter is, however, not quite so simple, 

 for the salts, owing to their ability to with- 

 draw water, also withdraw water from the 

 tissues into the blood, thereby increasing 

 the filtration stream through the glomeruli. 

 Cushny further showed that fixed constitu- 

 ents, like sodium chloride, may be reab- 

 sorbed, as in the case of the intestines, by 

 the epithelia of the tubules, that the diffi- 

 cultly diffusible Glauber salt was only 

 slightly and slowly reabsorbed, and that 

 finally urea is apparently not reabsorbed 

 at all. A further striking example of such 

 a renal diarrhoea, as I am inclined to call 

 it, has been brought forward by Loewi. 

 As I have already stated, every diuresis 

 dependent on increased glomerulus filtra- 

 tion occasions also an increased excretion 

 of sodium chloride and urea. If one poi- 

 sons an animal with phlorhizin there also 

 occurs an increased diuresis. This phlor- 

 hizin diuresis, as Brodie showed, appears 

 to be wholly independent, in general, of the 

 circulation and especially of the circulation 

 through the kidney. And, what particu- 

 larly interests us here, this diuresis is 



not dependent on the filtration of water 

 through the glomeruli, for, according to 

 Loewi 's analysis the chlorides and urea 

 were not excreted in increased amount, as 

 is the case in all the other forms of diuresis. 

 The phlorhizin diuresis must be regarded, 

 therefore, as a pure tubular diarrhoea, 

 brought about by the sugar excreted in 

 the tubules of the kidney itself and there 

 hindering the resorption of water by means 

 of its water-attracting properties. 



We have, therefore, in many instances 

 two closely connected processes which con- 

 stitute the basis of increased diuresis, the 

 interference with resorption from the 

 tubules, and the increased filtration through 

 the glomeruli, the latter being probably the 

 more important factor. The question arises 

 what are the conditions that determine the 

 operation of these factors ? It may be that 

 to a slight extent the diminished viscosity 

 of the blood or, more properly, the degree 

 of saturation of the colloids of the blood 

 with water are here concerned. We know 

 that in thirsting animals the kidney secre- 

 tion can not be increased in any way; we 

 have, therefore, no quantitative conception 

 of the extent of this influence. On the 

 other hand, we know of one factor which is 

 of determining significance for the process 

 of filtration. This is the blood flow through 

 the kidney. It was long ago shown by 

 E-oy that as a rule every diuresis is asso- 

 ciated with an increase in the volume of 

 the kidney, that is, sets in simultaneously 

 with an increased blood flow, and the ex- 

 periments of Roy have been repeatedly car- 

 ried out with essentially the same results 

 by numerous investigators, and especially 

 by Gottlieb and Magnus and by Starling 

 and Bayliss. Still it appeared from time 

 to time that there were exceptions in which 

 increased diuresis occurred in association 

 with an unchanged volume or scarcely per- 

 ceptible increase in the volume of the kid- 



