6 DISTRIBUTION OF HEMOGLOBIN AND ALLIED SUBSTANCES 



Griffiths (loc. cit.) gives the elementary composition of chlorocruorin as 

 and the empirical formula as 



RESPIRATORY METAL-FREE COLORLESS PROTEINS. 



The absence of colored respiratory substances from certain of the 

 invertebrates has been noted by a number of observers. Colored respira- 

 tor}' pigments in such animals, except in certain of the very lowest forms, 

 are doubtless represented by those without color. Griffiths (loc. cit.) has 

 described several colorless metal-free proteins which through their behavior 

 towards and CO 2 are to be regarded as being respiratory, and which 

 he believes are widely distributed among the invertebrates. From the blood 

 of Patella vulgata he states he obtained a colorless globulin which he dis- 

 tinguishes as a-achroglobulin. He gives to it the formula C 5 23H 761 N 196 S0 14 o 

 and states that 100 grams at and 760 mm. combine with 132 c.c. of O 

 and 315 c.c. of C0 2 . Its rotatory power in dilute magnesium sulphate solu- 

 tion he found to be [a] D = -48. 



From Chiton he obtained another form of respiratory globulin which 

 he designates /3-achroglobulin, to which he ascribes the formula 



Its combining capacity for 100 grams he determined to be at and 760 

 mm., 120 c.c. of and 281 c.c. of C0 2 . In dilute magnesium sulphate 

 solution, its rotatory power was [a] D = - 55. 



TABLE 1. The achroglobulins of Griffiths, and their empirical formulas, 

 oxygen capacities, and rotatory powers. 



A third form, distinguished as y-achroglobulin, he prepared from the 

 blood of tunicates (Ascidia, Mogula, Cyanthia). To this he gives the 

 formula C 7 2iH 915 N 194 S0 183 . Its rotatory power he found to be [a] D = - 63. 

 Its 0-capacity was 149 c.c. per 100 grams at and 760 mm. It also com- 

 bined with methane, CO, and acetylene. A fourth form, i5-achroglobulin, he 

 obtained from the mollusc Doris. The formula he gives as C 659 H 792 N 165 SO 153 

 and the combining capacity for O as 125 c.c. and the rotatory power as 

 [a] D = ."> 1 . This globulin combines with methane, acetylene, and ethylene 

 to form yellowish, greenish, and brownish compounds, respectively, which 

 are dissociable in vacuum. Similarities and dissimilarities of composition, 

 0-capacity, and rotatory power are shown in table 1. It is of particular 

 interest to note that the O-capacities compare most favorably with the 

 0-ca acitv of hemoglobin (134 c.c. Hiifner). 



