II.) - cells that are motile and extremely phagocytic to these bacteria.
If the abscess be deeply situated in some tissue and not able to open on to a free surface so allowing the contents to be drained off, the phagocytic cells play a very prominent part in the resolution of the abscess.
Wright and others, in recent work on opsonins, have shown that, by injecting dead cultures of the causal agent into subjects infected with the organism, there is produced in the body fluids a substance (opsonin) which apparently in favourable conditions unites with the living causal bacteria and so sensitizes them that they are readily taken up and destroyed by the phagocytic cells of tissues.
In the latter case they invade cells of a leucocytic or phagocytic character as a rule; Leishman's form is particularly abundant in large macrophageal cells originating from the vascular endothelium of the spleen (fig.
From the shape and position of the phagocytic organs it is obvious that they form admirable strainers through which the fluid of the body-cavity filters (figs.
The toxins produced by microbes, if too weak to destroy the leucocytes, induce them to secrete antitoxins, which not only act as antidotes to the toxins and are injurious to the microbes, but also increase the phagocytic power of the leucocytes (opsonius of Wright).
These phagocytic cells carry out the complete removal of all the injured warring elements and the damaged tissues of the part.
Note that these phagocytic cells are pushing out protoplasmic processes (pseudopodia) by which they grasp their victims. (X woo diam.) FIG.
By the aid of the new fibroblasts this fibrous tissue zone gradually encroaches on the pus area and replaces the phagocytic layer of cells as they proceed with the absorption of the pus mass (fig.
On the contrary the labile opsonins of normal serum have a comparatively general action on different organisms. It is quite evident that the specific immune-opsonins may play a very important part in the phenomena of immunity, as by their means the organisms are taken up more actively by the phagocytic cells, and thereafter may undergo rapid disintegration.