VOL. LXI.] PHILOSOPHICAL TRANSACTIONS. l63 



cause, and may be some effect of the repulsive force belonging to the polished 

 surface; but this point they did not sufficiently examine into, by a due repetition 

 of experiments. Mr. W, just mentions, that partly with a view to this matter, 

 they exposed as above, a set of bodies, having their surfaces of diftferent degrees 

 of polish, and as equally covered with frozen moisture as they could judge. The 

 result of which experiments seemed to favour the idea of the ice being less at- 

 tached to the more polished surface than to the coarser. Tliis appeared particu- 

 larly in the case of a comparison made between the speculum above mentioned, 

 and the brass end or cover of the same telescope; for the ice was found still to 

 cleave to its surface a good while after the speculum was entirely cleared. 



XXXIX. Some Experiments on Putrefaction. By F. L. F. Crell, M. D,, and 

 Professor of Chemistry at Brunsivich. p. 332. 



The celebrated Lord Bacon (Nat. Hist. Cent. 4.) has doubtless shown a very 

 great sagacity, in pointing out to posterity, putrefaction, as a subject worthy of 

 being further inquired into ; and as there happen daily so many changes, not 

 only in the inanimate, but also in the animate world, carried on by its means; 

 the knowledge of every thing relating to it must clear up a great many points in 

 natural philosophy, not thoroughly understood before. But these inquiries 

 ought to be of still more consequence to mankind, as health depends greatly on 

 keeping in due bounds putrefaction, which the body naturally tends to. For 

 these reasons. Sir John Pringle deserves, besides his other eminent merits, very 

 great praise, on his having made many experiments on this subject; and medicine 

 is indebted to him for considerable improvements resulting from them. He has 

 besides opened the way to many other gentlemen, among whom excel Dr. Gaber, 

 and Dr. M'Bride, whose numerous experiments show the ingenuity and sagacity 

 they are possessed of: but the subject is not yet exhausted, nor will it be very 

 easily. I have made some experiments relating to it ; and should be very glad 

 if they threw a new light on some points of the greatest importance to medicine. 



Dr. Gaber has proved, by his experiments, the presence of a volatile alkali 

 produced by putrefaction ; but as he did not discover by the same proceedings * 

 any in its beginning or end, though there was a very putrid smell, he denies its 

 existence in these states, and concludes that this volatile alkali is not a necessary 

 product of putrefaction. -|- This doctrine seemed not quite conformable to the 



• Acta Taurinens. vol. i. p 78. Cum attegerint sumtnum efFervescentiae gradum, continuato ejus- 

 dem loci calore efFervescentiae vim amiserunt. P. 79- Citius plerumqne prodiit foetor, quara alkali, 

 idemque tardiiis desiit. P- 82. Massam inde relinqui foetentissiraam, sed emisso alkali ad efFerves- 

 centiam ineptam. — Orig. 



fid. p. 83, 15. Quum foeteret gravissime residuum destillationis, quamquam orani alkali orba- 

 tum, manifestum videtur, ab alkali foetorem exsltari quidem posse, et magis penetrantem effici, non 



Y 1 



