IB NECROSIS OF TISSUES. 



e Pigment Granules, which, with the exception of iron 

 sulphide, are all derived from the colouring matter of the blood, 

 are found in the shreds which float in the sanies oozing from 

 vascular parts, and in the tissues of such parts themselves. 

 They exliibit a high degree of polymorphism. The most fre- 

 quent variety is a rust-coloured pigment, occumng in the form 

 of granules, either single or aggregated, vaiying from a yellow 

 to a dark reddish-brown tint ; this is closely related to ha3matin 

 in chemical composition, and is also met with in non-gangrenous, 

 so-called pigmentary metamorphoses of tissue, associated with 

 hsematoidin. It is only what are known as gangrene corpuscles 

 that are regarded as peculiar to necrosis ; these are minute black 

 particles of very irregular shape, only to be detected under high 

 magnifying powers, and which set most reagents at defiance. It 

 is by no means certain that these gangrene corpuscles are exclu- 

 sively associated with putrefactive changes; on the contrary, 

 there are good grounds for believing them to be identical with 

 Melanin, of which more will be said hereafter (fig. 2, e). 



§ 24. The occurrence of living organisms in gangrenous 

 parts is deserving of especial notice. I have shown already 

 that the process which we call putrefaction (Fiiulniss), and 

 which plays so great a part in necrosis, is exclusively due to the 

 presence and the vital activity of these humble organisms. 

 Manifold have been the disputes as to the animal or vegetable 

 nature of the minute, staff-shaped corpuscles which we see 

 in a state of continual rotator}^, gjTatory, or to-and-fro move- 

 ment (fig. 2, /). Even now that we know all about their 

 development, this question cannot be considered settled. They 

 originate as follows : their germs — dotlike particles of extreme 

 minuteness exhibiting lively movements — settle at the junction 

 of the putref)ang body with the air ; these germs become elon- 

 o-ated, and undergo repeated constrictions, forming long, jointed 

 threads, which are subsequently broken up into their component 

 joints ; these constitute the staff-shaped Bacteria. They form a 



needles may be produced, whose surface is studded with distinct pro- 

 jecting points." The larger spherules may also cohere. In doing so 

 they flatten each other; so that we not unfrequently come across 

 spherules flattened on one side, which have become accidentally detached 

 during mounting (fig. 2, a). 



