250 OF THE BLOOD: 



arrangements by which the lines in question can be examined, and the fore- 

 going woodcut, Fig. 116, is after a drawing by his hand. The uppermost 

 scale represents Mr. Sorby's standard interference spectrum, and is obtained 

 by transmitting light through two Nicol's prisms and an intervening plate 

 of quartz or selenite, with its axis at 45 to the plane of polarization. The 

 number of the dark bauds due to the interference of the luminous waves 

 may be regulated by the thickness of the plate of quartz, and for the sake 

 of convenience has been fixed at 12, the unequal dispersion making the 

 distance between the bands in the blue about twice as great as in the red. 

 The dark bauds are numbered 1, 2, 3, 4, etc., and the centre of the white 

 spaces 1-j, 2^, 3^, etc., which may be again subdivided, as into 1^, If, etc. 

 Definite narrow absorption bands are indicated by a * printed over their 

 centre. On this notation the bauds occurring in the several solutions men- 

 tioned may be described intelligibly and simply thus : 



* * 



2. Oxidized hemoglobin, . . 3| 4| 4| 5| 8 9 



* * 



3. Haemoglobin with CO, . . 3f 4J- 4| 5 8 9 and so on. 



According to Mr. Gamgee, 1 the nitrites cause blood to assume a chocolate 

 color, the bauds of oxidized haemoglobin becoming very faint, and an addi- 

 tional absorption baud in the same position as in acid hajmatin appearing. 

 The nitrites do not decompose the blood-coloring matter, nor discharge the 

 oxygen. They appear to link themselves on to it, as is probably the case 

 with hydrocyanic acid. 2 Nitritized blood absorbs less oxygen, but it can 

 convert into ozone what it does absorb. 



181. There can be no doubt that both the red and the colorless corpuscles 

 have, like other cells, a definite term of life; and that, whilst some are un- 

 dergoing disintegration, others are in a state of advancing development to 

 supply their places, so that the entire mass of both is undergoing continual 

 chauge. That a new production of red corpuscles may take place with con- 

 siderable rapidity we have evidence in the rapid restoration of their normal 

 proportion after it has been lowered by haemorrhage, and in the speedy in- 

 crease which may be effected in their amount in blood in which they have 

 been excessively diminished by disease, this being especially promoted by 

 the administration of iron, and by a generous diet. On the other hand, 

 various appearances indicative of degeneration may be seen in the red cor- 

 puscles; and this especially in the blood of the Oviparous Vertebrata, which 

 usually contains corpuscles almost destitute of color, and having a shrunken 

 or eroded aspect, their nuclei, however, presenting a remarkable distinct- 

 ness. That, under certain circumstances, such a degenerating process takes 

 place with great rapidity in the blood which circulates through the Spleen, 

 may be considered as ascertained almost beyond a doubt ( 157, in). The 

 duration of the individual corpuscles is unknown, the only evidence yet ob- 

 tained being derived from the experiments of Bernard, who found that 

 when the blood of birds was injected into the vessels of mammals, the ellip- 

 tical corpuscles of the former, which were at first plainly visible, disap- 

 peared entirely in the course of a few weeks. The question now arises, in 

 what manner the two classes of corpuscles are respectively developed, and 

 whether they have any relationship to each other. 



182. Development of the Blood-corpuscles. That the fully developed Red 

 corpuscles, when ceasing to exist as such, do not give origin to new corpus- 

 cles of the same kind, may now be asserted (notwithstanding the statements 



1 Proceedings of Koy. Soc., No. 102, 1868. 



2 Preyer, Virchow's Archiv, Bd. xl, 18G7; and Hoppc-Scyler, Untersuch., 1867. 



