i 
ONT REE COAGULATION OF THE “BLOOD 
THE CROONIAN LECTURE 
Delivered before the Royal Society of London, June 11, 1863. 
[Proceedings of the Royal Society of London, 1863.] 
THE subject on which I have the honour to address you this evening is 
one which lies at the foundation both of Physiology and Pathology, and, on 
account of its great importance, has engaged the best energies of many very 
able men, among whom may be mentioned, for example, such distinguished 
Fellows of this Society as John Hunter and Hewson; so that it might well 
seem presumptuous in me to hope to communicate anything new regarding it, 
were it not that the constant progress of Physiology and the allied sciences 
is ever opening up fresh paths for inquiry, and ever affording fresh facilities for 
pursuing them. Indeed, my difficulty, on the present occasion, does not depend 
so much on the lack of materials as on the complicated relations of the subject, 
which make me almost despair of being able, in the short time that can be de- 
voted to a lecture, to give, in anything like an intelligible form, even an adequate 
selection of the facts at my disposal. 
It may, in the first place, be worth while, more especially for the sake of 
any present who may not be physiologists, to mention very briefly some well- 
known general facts respecting the constitution of the blood. The blood, if 
examined by the microscope within the vessels of a living animal, is seen to 
consist of a liquid and numerous small particles suspended in it. The liquid 
is termed the ‘ liquor sanguinis ’, the particles the ‘ blood-corpuscles’. Of these 
corpuscles a few are colourless, and are named the ‘ colourless’ or “ white cor- 
puscles’. The great majority are coloured and cause the red appearance of 
the blood, and hence are called the ‘red corpuscles’. Soon after blood has 
been shed from the body, it passes from the fluid into the solid form. This 
depends upon the development in the blood of a solid material termed ‘ fibrine’, 
so called from its fibrous nature, consisting, as examined by the naked eye, of 
tenacious fibres, and having the same character also under the microscope. 
These fibres form a complicated network among the blood-corpuscles, and from 
their tenacity are the cause of the firmness of the clot. Soon after the process 
of solidification or coagulation is complete, the fibrine exhibits a disposition to 
