ox THE PHYSIOLOGICAL EFFECTS OF rEPTONE. 727 



to the reappearance of peptone at all in the urine after injection into the 

 circulation. 



Schmidt- Malhei7n,^ who &vst studied the question, used large doses, and 

 obtained suppression of urine lasting from twenty to ninety minutes. In 

 the urine subsequently passed he detected no peptone. Fano - obtained 

 similar results, as did also Grosjean^ many years later, both likewise 

 employing large doses. Ilo/meister,* meanwhile, had however shown that 

 these substances reappeared very quickly in the urine, and devised an 

 ingenious method, based upon the depth of tint given by the biuret re- 

 action, for estimating how much proteid became excreted. He corrected 

 his estimation by the use of the polarimeter, and came to the conclusion 

 that 6G to 80 per cent, of the peptone introduced was expelled from the 

 body within twenty-four hours. Owing to ditRciilties in the employment 

 of these methods, neither can be regarded as capable of yielding accurate 

 results. This is, indeed, admitted by the author, and, as we shall see, the 

 figures he arrived at are a good deal too high. 



In the earlier experiments of this research, no other sufficiently reliable 

 method of estimating the amount of peptone or alburaose excreted was 

 apparent. From the first, it was seen that the substance appeared only 

 in the urine secreted during the hour immediately following the injection, 

 and from the depth of the biui-et tint it was obvious that not nearly all 

 the proteid injected came out again. 



On more close examination it was found that the output of proteid was, 

 as a rule, confined to the urine of the first forty or forty-five minutes 

 succeeding the injection. It was also seen, on comparing the urea nitrogen 

 of this period with the total nitrogen of the same time (which included 

 that of the excreted proteid), that the whole difference was considerably 

 ess than the nitrogen injected. But this difierence included the nitrogen 

 of other compounds than urea, which I .shall subsequently call ' extractive ' 

 nitrogen. If a safe deduction, to represent the 'extractive' nitrogen, 

 could be made, then we should have ascertained the amount of proteid- 

 nitrogen which reappeared. Such a deduction was arrived at by basing a 

 calculation on the ' extractive ' nitrogen of the urine secreted immediately 

 after the peptone or albumose ceased to come out. When this was accom- 

 plished in forty to forty-five minutes, the urine of the remaining part of 

 this hour furnished the basis of calculation. The same principle was, 

 however, applied to many of the earlier experiments. The deduction in 

 these cases was calculated on the ' extractive ' nitrogen of the third hour, 

 and the subtraction made from the ' difference ' nitrogen of the whole of 

 the preceding hour. 



In both cases the urine which furnished the basis of calculation was 

 more dilute than that of the peptone (or albumose) excretion-period ; con- 

 sequently, the amount deducted is safe, in the sense of being under rather 

 than over the mark. 



In the following table, which gives a succinct statement of the facta 



' Schmidt-Mulheim, ' Beitrage zur Kenntniss des Peptons und seiner Physiolo- 

 gischen Bedeutung,' Archiv f. Physiohg, 1880, p. .S3. 



- Fano, ' Das Verhalten des Peptons und Tryptons gegen Blut und Lymphe,' 

 Archiv f. Physiolog, 1881, p. 277. 



' Grosjean, ' Recherches sur I'Action physiologique de la Propeptone et de la 

 Peptone,' Travail du Lah. de Physwlogie de VUniv. de Lilge, tome iv. 1891-92. 

 Also Archiv. de Biologic, 1892, xi. p. 381. 



* YLotxaQisier, Zeitschriftf. Pliijdolog's'lie Ch'viie, 1881, p. 127. 



