PART II.] Peculiar Microscopic Appearance of the Black Matter. 369 



assistance we have already had occasion to acknowledge in this Report, giving a brief 

 account of the result of examinations of fragments of the black substance which he 

 kindly undertook at our request. According to Mr. Wood the material yielded — 



Moisture (by drying at 100° C.) ... ... ... 76-7 



Mineral matter ... ... ... ... ... 1-4 



Organic matter (containing a trace of fat soluble in ether) ... 21"9 



100-0 



" In the dry state," Mr. Wood writes, " it is quite brittle and may be powdered. 

 The ash is of a red colour from the presence of oxide of iron, but consists chiefly of 

 calcium phosphate. The substance is unaffected by boiling water or acetic acid. Dilute 

 hydrochloric acid gradually extracts a little colour from it, but the alkalis are its only 

 solvents. It forms with potash a brown solution and softens in ammonia undergoing 

 partial disintegration. In its chemical characters this substance somewhat resembles 

 elastic tissue." 



The solution of the black material obtained, after subjecting the substance to 

 prolonged ebullition in distilled water, does not yield any characteristic appearance 

 when examined with the spectroscope ; nor does a similar solution when treated with 

 sulphuric acid. When, however, some of the material has been dissolved in caustic 

 potash and examined with the spectroscope, it is found that the solution obscures the 

 violet end of the spectrum as far as about the middle of the green — the violet and 

 nearly all the blue being completely absorbed. Blood treated with potash yields a 

 very similar spectrum, but we could not make out the absorption bands of hsematine 

 in any of the numerous solutions in which the darkened substance had been macerated. 



It is the microscopical appearance of this material, however, which presents 

 the most marked peculiarity ; that is to say, its microscopical appearance after a more 

 or less prolonged immersion in liquor potassse. The most satisfactory method of 

 procedure is to crush a lump of the material about the size of a hazel nut, and place 

 it in a test tube with about half an ounce of a strong solution of potash : when set 

 aside for three or four days, it will generally be found that the granular consistence 

 of the substance has disappeared, the fluid has become of a dark colour, which subsequently 

 passes into a pale sherry colour, and that a small flocculent sediment has subsided in 

 the tube — not more than one-fiftieth, however, of the amount of material introduced. 

 A little of this should be carefully transferred on to a drop of water placed on a glass 

 slide, very gently spread out by means of needles, a covering glass applied and the 

 slide examined under a power of from three to five hundred diameters. 



The woodcut on the following page very accurately represents what will, in all probability, 

 be observed (Fig. 13), mz.^ numerous branching filaments, septate and perfectly translucent, 

 mixed to a greater or less extent with empty looking cellular bodies. Morphologically 



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