PART II.] Structure and Composition of the Peculiar Bodies. 359 



11. Sul-phide of Carbon. — The action of this resembled that of the two previous 

 re-agents. 



12. Heated Oil. — Prolonged immersion in olive oil at 212° F. produced no effect 

 on the particles, save perhaps a slight alteration in their colour. 



13. Heat.— On placing particles on a capsule or sheet of platinum and exposing 

 them cautiously to the heat of a spirit lamp, they were found to become blackened 

 almost immediately, their surfaces assuming a jet black colour and glistening appearance, 

 as though they were partially melted. At the same time their outline frequently 

 became somewhat irregular, and a distinct but very transitory smell resembling that 

 of burned feathers was given off. On subsequently applying the blow-pipe and 

 subjecting them to a bright red heat for a moment, the particles were found on 

 examination to have become partially white — in many cases almost entirely so — a 

 mere sprinkling of minute black points remaining on the surface. When still further 

 heated, all blackness finally disappeared, and the particles were either pure white or 

 partially white and partially rusty brown, in colour. Though possibly somewhat smaller 

 than they had been previous to exposure to heat, they yet retained their characteristic 

 forms almost intact, and by careful manipulation could be removed entire and submitted 

 to microscopic examination. They were then found to consist of shells or skeletons 

 of inorganic matter, the particles of which had a more or less crystalline aspect. 



Their outlines, and general forms under the microscope too, were very frequently 

 almost identical with those of the original red particles. The material of which they 

 were composed was either entirely colourless or more or less stained, of a bright rusty 

 brown or yellowish tint. When the former was the case, they were entirely soluble 

 in weak acids, the solution varying in rapidity in different instances. In some cases 

 it was accomplished quietly and without any evolution of gas, whilst in others effervescence 

 occurred in various degrees. When, however, any rusty brown matter was present 

 this remained in great part unaffected by dilute acids, but was readily soluble in strong 

 hydrochloric acid, and if ferrocyanide of potassium were then added to the solution an 

 immediate development of blue colour took place. The presence of considerable quantities 

 of iron in the ash of the particles may perhaps be even more strikingly demonstrated, 

 in many instances, by treating the skeletons of the particles with weak acid whilst still 

 on the platinum, and then adding the ferrocyanide, when each particle immediately 

 becomes of a deep Prussian blue. 



Such have been the results of our investigations into the structure and composition 

 of these peculiar bodies, and we have now to consider the question of their real nature. 

 Save in regard to some vague points of form, they present nothing which can in any 

 way suggest that they are of a vegetable or parasitic nature. Even in regard to form, 

 too, they show nothing which may not frequently be found in concretions of various 

 kinds ; for, although some of the appearances may in some degree appear to suggest a 

 process of multiplication by cell division, they may all be readily accounted for by mere 

 mechanical processes of aggregation and fracture. Taking everything into consideration, 



