236 



On the Colouring-matters of Human Urine. [Dec. 16, 



Spectrum 6. Thinner stratum of the same. 



„ 7. Alcoholic extract of human bile pigments. 



„ 8. The same treated with sulphide of ammonium, showing the presence of 

 hsemochromogen. 



„ 9. Alcoholic extract of human bile pigments with peroxide of hydrogen, 



violet stage. 

 ,, 10. The same — end of reaction. 



„ 11. The absorption-band of serum, from blood of sheep (showing also 



O -haemoglobin bands) . 

 „ 12. Spectrum got by treating alcoholic extract of sheep-bile pigments with 



caustic soda for a short time. 

 „ 13. Spectrum closely resembling lutein got by longer action. This spectrum 



was also produced from hcematin reduced by sodium amalgam, or at 



all events a spectrum very Wee it, by someivhat similar treatment. 



Table giving the wave-length corresponding to each division of the 

 scale in millionths of a millimetre. 



Scale reading. 



Wave-length. 



28 

 29 

 30 

 31 

 32 

 33 

 34 

 35 

 36 

 37 

 38 

 39 

 40 

 41 

 42 

 43 

 44 

 45 

 46 

 47 

 48 

 49 

 50 

 51 

 52 

 53 

 54 

 55 



683 

 671 

 660 

 654 

 646 

 639 

 632 

 625 

 620 

 614 

 608 

 603 

 598 

 593 

 588 

 584 

 580 

 576 

 571 

 567 

 562 

 558 

 555 

 550 

 546 

 542 

 538 

 534 



Scale reading. 



56 

 57 



58 

 59 

 60 



"Wave-length. 



530 



526 

 523 

 520 

 516 



61 513 



62 510 



63 507 



64 504 



65 501 



66 499 



67 496 



68 493 



69 491 



70 488 



71 486 



72 484 



73 482 



74 480 



75 478 



76 476 



77 474 



78 472 



79 469 



80 467 



81 465 



82 463 



83 461 



