PART II.] Nature of the Red Particles. 357 



In the present case the red colouring was absolutely confined to the particles ; 

 there was no staining of the tissues in connection with which they occurred. The 

 particles, as previously stated, immediately attracted attention, as an abundant sprinkling 

 of minute, bright red points or grains scattered over the tissues and deposited on the 

 sides and bottom of the vessel containing the preparation. Their size varied considerably 

 in different instances, but in the greater number ranged from j-|/ x y|/ to yV x -^q". 

 Their outline was generally rounded or oval, but many more or less irregular forms 

 also occurred ; these might, however, be almost always ascribed to the occurrence of 

 fracture or rupture of the commoner forms, or to the union of several particles into 

 an aggregate {vide Plate XXVII, Figs. 3 — 4). 



The figures in the plate show the principal varieties of forms present, and that 

 they were all modifications of the round or oval primary one. Many of them, in place 

 of having an even surface, were more or less tuberculated or knotted; others were 

 constricted in the middle, or even actually separated into two portions with an intervening 

 space ; others were aggregated longitudinally in a moniliform fashion, or formed irregular 

 heaps ; whilst others again were ruptured and, as it were, unfolded. The colour, when 

 fully developed, appeared bright vermilion to the naked eye, and under the microscope 

 passed from this into a rosy carmine, according to the degree of magnifying power 

 employed. The colour of the particles was, however, by no means uniform in intensity in 

 all instances, a faint red or pinkish tinge being all that could be determined in many ; 

 whilst in others the red colouring was entirely absent, and they were of a dull buff 

 or yellowish hue. The latter particles did not, in other respects, in any way differ 

 from the most highly coloured particles in appearance. In some cases, as fractured 

 specimens showed, the particles were solid and seemingly homogeneous throughout, 

 but in others they appeared to contain a central cavity — ^an appearance which, as will 

 appear farther on, was not a deceptive one. 



When examined under comparatively high powers, from 400 to 1,500 diameters, 

 they appeared to be composed of a finely molecular material. In some instances they 

 presented a homogeneous aspect, but in others they had more or less of a cellular 

 appearance, being marked out into areas by obscure double lines. This appearance 

 was, in some cases, not dependent on any true cellular structure, but was due to the 

 existence of irregular fissures running through the substance of the particle and extending 

 from the central cavity when the latter was present. In other instances, however, the 

 phenomenon appeared to be of a different nature, and the structure of the particles 

 seemed yet to retain the traces of the fat cells out of which they had been formed. 



Beyond these characters nothing could be ascertained regarding the nature of these 

 particles by microscopic examination alone, and recourse was accordingly had to the 

 use of reagents. In working at the chemistry of the subject, we had the great benefit 

 of the advice of an accomplished chemist, Mr, C. H. Wood, the Quinologist to 

 Government, who not only suggested the use of various tests, but also tried some of 

 them for us himself. We shall now give an account of the effects produced by the 



