40 r»R. BASTIAN ON THE 



a very appreciable .rate, even at the comparatively low tempera- 

 ture of 83° F.* 



These experiments show the amount of change which goes on 

 in one of the principal constituents of urine during the time that 

 it is being boiled over the flame or in a closed vessel, and also 

 during the probation-period to which it was subjected in the 

 attempts made by Dr. Roberts and Professor Tyndall to improve 

 upon my experiments. It is extremely unlikely tliat this is the only 

 change which the constituents of urine undergo ; but the aid of 

 the chemist is needed to enlighten us further upon this subject. 



I am strongly inclined to believe that urine, where it does not 

 ferment soon after being placed in tlie incubator, gradually lapses 

 (like other organic fluids when, under similar conditions, they 

 remain sterile) into a more stable condition through the superven- 

 tion of slow chemical changes. This opinion is based upon the 

 fact that such specimens of urine are found to be notably less 

 prone to undergo fermentation when the necks of the vessels are 

 broken and the fluids are freely exposed to the atmosphere, than 

 specimens otherwise similar which have been exposed to the air 

 within a few tours after having been boiled to the same extent. 

 Barren urine which has been many days exposed to a tempera- 

 ture of 122° F. will remain for days — or even for weeks, in many 

 cases — in free communication with the air, without fermenting or 

 showing any signs of change f. The urine is, indeed, reduced to a 

 * A few other estimations have been made of separate specimens of urine 

 (though tliey were all of about the same acidity and specific gravity) after ex- 

 posuj-e for different periods to a temperature of 122° F. These I subjoin : — 



1. Urine of sp. gr. 1020... Boiled l"over flame. "1 



Acidity per oz. = m. X. „ 10" in can. ^ Acidity =m.v^ of liq. pot. 



At 122° F. for 11 days. J 



2. Urine sp. gr. 1020 Boiled fori "over flame, "l a -j-j. • t 



Acidity =m. x. At 122° F. for 20 days. } ^""'^'^^ ='^- '^ ^^l" P°*- 



3. Urine sp. gr. 1022 Boiled for2"over ilame. "I a -j-, --it , 



Acidity =m. X. At 122° F. for 40 days. ) ^""^^^^ =°^- "* ^^l" ?«*• 



4. Urine sp. gr. 1020 Boiled for 5"overflame. ") . .■,., . ,. . 



Acidity =m. X. At 122° F. for 6 days, j ^''^'^ =^- ^^- ^^l" P^*" 



t And when they do ferment, it is worthy of note that the organisms which 

 appear (if not Moulds) are still Bacilli. Is it therefore that air-infection always 

 yields this form because its germs are omnipresent, or because there is a corre- 

 lation between the germs of any of these variable lowest organisms and many 

 boiled fluids, of such a nature as commonly to lead to the development of 

 Bacilli? The latter interpretation very much weakens the force of Prof. 

 Oohn's inference from the fact of the frequency with which this form manifests 

 itself in boiled and guarded fluids, viz. that its spores are able to survive boiling 

 after desiccation (see p. 73). The former interpretation is so improbable that 

 it has not yet been advanced. 



1 



