246 OF THE BLOOD: 



alcohol, or by some salt or acid. Some of the chief forms of haemoglobin 

 crystals are exhibited in Figs. Ill, 112, 113. It has beeu ascertained 

 that with the exception of those of the squirrel, which are hexagonal, the 

 crystals of the blood of other animals belong to the rhombic system. Those 

 of man present the form of elongated rectangles, rhombs, and four-sided 

 prisms, with dihedral summits. The crystals of the blood of the rabbit are 

 very similar to those of man. Those of the dog are long four-sided needles, 

 terminated by one plane surface. From cat's blood similar crystals may be 

 obtained, together with thin rhombic and six-si'ded plates. In the guinea- 

 pig tetrahedra, and in the rat tetra- and octahedra are found. Dr. Ray 

 Laukester 1 has shown that Haemoglobin is present in the plasma of the vas- 

 cular fluid of various Invertebrata, as in that of the Annelids Lumbricus, 

 Eunice sanguinea and Hirudo, in that of the Crustacean Phyllopod, Cheiro- 

 cephalus diaphauus ; in that of Chirononius amongst Insecta and the Plaii- 

 orbis amongst Mollusca. 



Haemoglobin crystals, from whatever animal they may be obtained, are 

 always perfectly transparent, and doubly refracting, with silky lustre; the 

 crystals of reduced haemoglobin are pleochromatic, alternating from red or 

 purple to green ; but those of oxygenated haemoglobin are not so, present- 

 ing the color of the blood from which they are got. When fresh they are 

 soft and highly elastic, breaking with an uneven splintery fracture; exposed 

 to the actipn of water they imbibe it and undergo various changes of form, 

 never, however, assuming that of a red blood-corpuscle. The sp. gr. of 

 haemoglobin probably varies from 1.3 to 1.4. All the varieties are soluble 

 in water, and the solubility increases with the temperature. They are in- 

 soluble in absolute alcohol, ether, in volatile and fixed oils, benzol, turpen- 

 tine, chloroform, and carbon disulphide. They dissolve readily and for 

 some time without undergoing decomposition in the alkalies and most alka- 

 line salts (carbonates, phosphates, borates), but in a few days the solution 

 becomes cloudy from decomposition. Solutions of most acids quickly dis- 

 solve them, but decomposition sets in in the course of a few hours. They 

 remain long unchanged in healthy urine, in saccharine solutions, in bile, 

 and serous transudates. Haemoglobin, though a crystalline compound, is 

 not diffusible, and when pure is not fibrino-plastic. The percentage com- 

 position of haemoglobin obtained from Schmid's and Hoppe-Seyler's analy- 

 ses is C 54.0, H 7.25, N 16.25, iron 0.42, sulphur 0.63, O 21.45, which 

 accords with the formula: C 600, H 960, N 154, Fe^S,, O 179. 2 Haemo- 

 globin has a strong affinity for oxygen, one gramme absorbing at mean tem- 

 perature and pressure 1.3 cub. cent, of this gas, but at the same time it 

 readily yields up the gas to other easily oxidizable substances. 



179. Under the influence of warmth (140-180 F.), of acids, or of caus- 

 tic alkalies, haemoglobin undergoes decomposition ; the color of the liquid 

 changes from a beautiful red to a smutty tint, which appears in thin layers 

 and by reflected light, brown, and by transmitted light, green. This change 

 of color is due to the breaking up of the haemoglobin into an albuminous 

 compound, and a peculiar colored substance termed Juematin. Every 100 



i Journal of Anat. and Physiology, 1808, p. 114, and 1871, p. 122, and Proceed, of 

 Hoy. Soc., 1872, Dec. 12th. 



- According to the recent researches of MM. Paquelin and Jolly (Seance do 

 1' Academic des Sciences, 19th Oct. 1874), the corpuscles of the blood contain the 

 iri. 11 in the form of tribasic phosphate of the protoxide, but the pure coloring mat- 

 ter (their ha-matosin) contains no iron. Their ha-matosin burns away without leav- 

 ing an}' ash, is insoluble in pure water, slightly soluble in solutions of ammonia, 

 potash, and .soda, undergoing decr.nipoMiion in the two latter; soluble in ether, 

 chloroform, benzin, and bisulphide of carbon. 



