358 Dr Newbigging on certain Cireumstances affecting 



The fact of the succession, therefore, and of the constant 

 succession, constitutes alone the unity of the species. Thus, 

 unity, absolute unity, of the human species, and variety of its 

 races, as a final result, is the general and certain conclu- 

 sion of all the facts acquired concerning the natural history of 



On certain Circumstances affecting the Colour of Blood during 

 Coagulation, t By Patrick S. K. Newbigging, M. D. 

 F.R.C.S.E., formerly Senior President of the Royal Medi- 

 cal Society, one of the Medical Officers of the New Town 

 Dispensary, &c. (Communicated by the Author.) 

 During the summer of 1834, whilst engaged in prosecuting 

 some inquiries into the state of the blood in eruptive diseases, 

 my attention was called to the appearance of various vermi- 

 lion-coloiu"ed spots, represented upon that portion of the coagu- 

 lum which had been in contact mth the lowest part of the 

 cup, in which the blood dravni from a patient had been received. 

 On examining the interior of the cup, I found that the outline 

 of that portion of the ornament which was of a green colour, 

 corresponded exactly with the figure of the vermilion-coloured 

 spots on the clot ; upon the rest of which, where in contact 

 with any of the other colours with which the interior of the 

 cup was decorated, no change was observable. The circum- 

 stance appearing curious, and not as yet, as far as I knew, 

 noticed, I stated the fact in a short communication to the 

 Royal Medical Society. Thereafter I was induced to repeat 

 the experiment with the same cups in several instances in 

 which I had occasion to draw blood, and always with a similar 

 result ; the green invariably striking a bright red, contrasting 

 strongly with the dark hue of the surrounding coagulum. 

 With the view of satisfying myself that the appearances were 

 altogether unconnected with any diseased condition of the 

 blood, I procured an individual in perfect health, from whom 

 I let blood in the ordinary way. In this, as in other instances, 



* Annales des Sciences, Nat. t. x., Dec. 1838, pp. 361, &c. 



+ Read before the Royal Society of Edinburgh, March 1839, by Professor 

 Forbes, who, along with Sir John Robison, witnessed several of the experi- 

 ments. 



