Comparative pathology of inflammation in the sheep : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University, Palmerston North, New Zealand

Abstract

The inflammatory reaction is fundamental to the survival of the organism. It cannot be over-emphasised that without it there could be no protection against the effects of noxious external stimuli nor repair of damaged tissue (see Ebert, 1965). The inflammatory response, however, has attracted renewed interest in recent years with the realisation that inflammation may become aberrant and considerably more harmful to the body than the noxious stimulus which initiated the reaction. Thus, in some diseases a large portion of tissue damage results from the inflammatory response itself. Allergic and rheumatic diseases fall into this category (see Spector and Willoughby, 1963a). Ebert (1965) suggests that " ...... within certain limits the inflammatory reaction is stereotyped and it cannot distinguish between those instances in which the process protects the host and those in which the host is harmed". Inflammation is difficult to define. Spector and Willoughby (1963a) have suggested that, "In vertebrates it could perhaps be described as the local reaction to injury of the living microcirculation and its associated tissues, in which would be included blood leucocytes and such features of perivascular tissue as mast cells and histiocytes". More recently, Ebert (1965) in an attempt to define inflammation pointed out that "It is difficult to give a definition which is neither so all-inclusive as to be meaningless nor so specific that it is too restrictive.", and suggested that "Inflammation is a process which begins following a sublethal injury to tissue and ends with complete healing".