§ 41 •] SPECTROSCOPIC APPEARANCES OF BLOOD. 67 
Riegler 1 has suggested the best general test for blood at present 
known. 
Riegler’s reagent is prepared as follows :—10 grins, of sodium hydroxide 
are dissolved in 100 c.c. of water ; to this 5 grms. of hydrazin are 
added, and the whole shaken ; lastly, alcohol of 96-97 per cent, is 
added in equal volume, the mixture shaken, allowed to stand for two 
hours, and filtered ; the filtrate is used as the reagent. 
Oxyhaemoglobin. 
Methaemoglobin and 
Oxyhaemoglobin. 
Haemoglobin. 
Acid Haematin. 
Alkaline Haematin 
(aqueous solution). 
Alkaline Haematin 
(alcoholic solution). 
Haemochromogen 
(reduced Haematin). 
Haematoporphyrin 
(acid solution). 
Haematoporphyrin 
(alkaline solution). 
Sulphaemoglo bin. 
Carbon monoxide 
haemoglobin. 
The reagent can be added to one or two drops of blood in a test 
tube, or be used as a solvent for stains on wood, iron, and so forth. 
It may also be used as a reagent for blood in urine, milk, and other 
fluids, if the blood is small in quantity. In non-albuminous fluids, it 
is advisable to add a little albumin, acidify with acetic acid, heat to 
boiling, and treat the separated coagulum with the reagent. 
The solution is of a fine purple-red colour ; and whether the colouring- 
matter be derived from blood, oxyhemoglobin, methaemoglobin, or 
haematin, the two bands of haemochromogen can be seen in the suitably 
1 “ Ein neues Reagens zum Nachweis der verscliiedonen Blutfarbstoti'e odor dor 
Zersotzungsprodukte dorselben,” Zeit. f. anal. Chemie, 1904, 539. 
