If at any part adhesion fail, suppuration and granulation must follow. The adhesion may be prevented by any of the circumstances already mentioned, or by an unfavourable state of the constitution, the nature of the wound, exposure to bad air, the occurrence of fever, or of a flux natural or not. The wound may contain foreign matter; blood or the contents of canals may be effused into it, and many other obstacles may exist to retard, or prevent adhesion. Notwithstanding, in all cases, though the chance of union be but small, the parts should be approximated. A great point is gained if certain parts only are brought to adhere, for by their natural attachments the opposite surfaces are preserved in more direct contact than they could otherwise be, and thereby but little space remains to be filled up with granulations. If, on the contrary, the surfaces are not approximated, the flap is diminished in size, and when afterwards placed in contact with the surface from which it was detached, it is found not to correspond, leaving considerable deficiency to be repaired by the comparatively slow process of granulation. Whereas, if it had been early replaced, partial attachments would probably have been formed by adhesion, the flap thereby retained in situ, and prevented from shrinking, so that but little new matter would be required. Sometimes union does occur, and that speedily, after the flap has remained separate for a considerable time; and in such cases it may be doubted, whether union is accomplished by adhesion, strictly so called. Most probably it is by this process that the rapid union occurs in such circumstances: the divided parts have assumed an excited action, and effused lymph; during their state of separation, the lymph will become organised when it is connected with the original parts, just as well as if the surfaces had been in contact; and when they are at length so placed, they will be agglutinated to each other by the outer part of the effused lymph, which still continues soft and unorganised. If motion be then prevented, organisation, which has already commenced in the connecting medium, will proceed undisturbed, converting the agglutination of soft unorganised lymph into firm and permanent union by means of organised tissue. In these circumstances, it is not to be wondered at if adhesion should be completed in a shorter time than when the surfaces are brought together immediately after their division; in each instance the process is the same, only in the one it has to proceed from its very commencement, whilst in the other it is previously all but perfected, and after the parts have been put together, the last stage only requires completion. It is only in a particular stage of a granulating surface, that adhesion will take place speedily, when the discharge is diminished, but healthy, and the granulations florid and firm.