OTHER COMPOUNDS OF HEMOGLOBIN. 25 



stimulation and afterwards paralysis of the nervous system, as shown by the symptoms induced, 

 e.g., violent headache, great restlessness, excitement, increased activity of the heart and respira- 

 tion, salivation, tremors, and spasms. Later, unconsciousness, weakness, and paralysis occur, 

 laboured respiration, diminished heart-beat, and lastly, complete loss of sensibility, cessation 

 of the respiration and heart-beat, and death. At first the temperature rises several* tenths of a 

 degree, but it soon falls 1 or more. The pulse is also increased at first, but afterwards it 

 becomes very small and frequent. In poisoning with pure CO there is no dyspnoea, but some- 

 times muscular spasms occur, the coma not being very marked. There is also temporary but 

 pronounced paralysis of the limbs, followed by violent spasms. After death the heart and brain 

 are congested with intensely florid blood. In poisoning with the vapour of charcoal, where 

 CO and C0 2 both occur, there is a varying degree of coma ; pronounced dyspnoea, muscular 

 spasms which may last several minutes, gradual paralysis and asphyxia, moniliform contrac- 

 tions and subsequent dilatation of the blood-vessel's, with congestion of various organs, occur, 

 accompanied by a fall of the blood-pressure (Klebs), indicating initial stimulation and subsequent 

 paralysis of the vaso-motor centre. This also explains the variations in the temperature and 

 the occasional occurrence of sugar in the urine after poisoning with CO. After death, the 

 blood-vessels are found to be filled with fluid blood of an exquisitely bright cherry red colour, 

 while all the muscles and viscera and exposed parts of the body (such as the lips) have the same 

 colour. The brain is soft and friable ; there is catarrh of the respiratory organs and degenera- 

 tion of the muscles, and great congestion and degeneration of the liver, kidneys, and spleen. 

 The spots of lividity, yost-mortem, are bright red. After recovery from poisoning with CO 

 there may be paraplegia and (although more rarely) disturbances of the cerebral activity. 



17. OTHER COMPOUNDS OF HEMOGLOBIN. 4. Nitric Oxide-Haemo- 

 globin (NO-Hb) is formed when NO is brought into contact with Hb (Z. 

 Hermann). 



As NO has a great affinity for 0, red fumes of nitrogen peroxide (N0 2 ) being formed when- 

 ever the two gases meet, it is clear that, in order to prepare NO-Hb, the must first be 

 removed. This may be done by passing H through it, [or ammonia may be added to the blood, and 

 a stream of NO passed through it ; the ammonia combines with all the acid formed by the union 

 of the NO with the of the blood]. NO-Hb is a more stable chemical compound than CO-Hb, 

 which, as we have seen, is again more stable than 2 Hb. It has a bluish-violet tint, and also 

 gives two absorption-bands in the spectrum similar to those of the other two compounds, but 

 not so intense. These bands are not abolished by the action of reducing agents. As NO-Hb 

 cannot be formed in the body, it has no practical significance. 



The three compounds of Hb, with O, CO, and NO are crystalline, like reduced 

 Hb ; they are isomorphous, and their solutions are not dichroic. All three gases 

 unite in equal volumes with Hb. If O be conducted through a concentrated 

 solution of Hb devoid of gases, a crystalline mass of 2 Hb is thereby readily 

 formed. 



5. Cyanogen, CNII (Hoppe-Seyler), and acetylene, C 2 H 4 (Bistrow and Licbrcich), form easily 

 decomposable compounds with Hb. The former occurs in poisoning with hydrocyanic acid, and 

 has a spectrum nearly identical with that of 2 Hb, and, like 0. 2 Hb, it is reduced, but very 

 slowly, by special reagents. [The existence of these compounds is, however, highly doubtful 

 (Gamgee).] 



18. DECOMPOSITION OF HEMOGLOBIN. In solution and in the dry 



state Hb gradually becomes decomposed, whereby the iron-containing pigment 

 haematin (along with certain bye-products, formic, lactic, and butyric acids), is 

 formed. Haemoglobin, however, may be decomposed at once into (1) Haematin, 

 a body containing iron, and (2) a colourless proteid closely related to globulin ; by 

 (a) the addition of all acids, even by C0 2 in the presence of plenty of water ; (6) 

 strong alkalies ; (c) all reagents which coagulate albumin, and by heat at 70-80 

 C; (d) by ozone. 



(A) Haematin, C 32 H 32 N 4 Fe0 4 (NencH and Sieber), is a bluish-black amorphous 

 body, which forms about 4 per cent, of haemoglobin (dog). It is insoluble in water, 

 alcohol, and ether ; soluble in dilute alkalies and acids, and in acidulated ether and 

 alcohol. 



(1) Acid Haematin. Lecanu extracted it from dry blood-corpuscles by using 

 alcohol containing sulphuric and tartaric acids. [If acetic acid be added to a 

 solution of Hb and slightly heated, a mahogany-brown fluid is obtained, containing 



