THE MITOCHONDRIAL CONSTITUENTS OF PROTOPLASM. 115 



become resorbed and ^o into solution in the cytoplasm, for we have good reason 

 to believe that the mitochondria do go back into solution (p. 98). These are not 

 all the points that must be cleared up before we can look upon this question of the 

 actual chemical transformation of mitochondria into plastids as being definitely 

 settled. The work which has lieen done so far is extremely suggestive, but it is 

 not conclusive. 



The evidence seems to point to the conclusion that the single chloroplasts in 

 some of the algae do not arise from mitochondria, because mitochondria are absent, 

 so that they would constitute an important exception to the general rule. It is 

 thought, moreover, that these single plastids perform a similar function to that of 

 those in the adult cells of higher plants, where the mitochondria are either absent 

 or greatly reduced in number. This, by Sapehin, is brought forward as evidence 

 against the view that mitochondria are transformed into plasts. It is necessary 

 to find out whether the chlorojilasts in animals, some varieties of Faramocciuin 

 for example, are formed from mitochondria in the same way that has been claimed 

 in plants. Information on this point is urgently needed, because it would tell us 

 whether animal mitochondria are capable of performing the same feats which have 

 been ascribed to vegetable mitochondria, and give us an idea of the degree of 

 resemblance of mitochondria in the plant and animal kingdoms. Varying degrees 

 of chlorophyll production, caused by regulating the illumination, should be studied. 

 It would be interesting to note whether phosphatids outside the body are capable 

 of entering into close combination with starch and chlorojihyll. And, finally, 

 experiments might be devised to show whether animal mitochondria and plant 

 mitochondria, in species devoid of chlorophyll, are able to pick up and condense 

 starch and chlorophyll when they are brought into intimate contact with them, 

 which would have a very important bearing upon this question of the transforma- 

 tion of mitochondria into plastids. 



PIGMENTS. 

 HEMOGLOBIN. 



Ciaccio (1911, p. 16), in October, arrived at the conclusion that hemoglobin 

 is formed under the influence of mitochondria on the basis of his observation that, 

 in the rabbit, not only the basophilic erythroblasts but also those provided with 

 hemoglobin, and the erythrocytes, just before they enter into the circulation, con- 

 tain typical mitochondria. In October, also, Meves (1911a, p. 495) published 

 identical results relating to the red blood-cells in the bone marrow of the guinea-pig. 



A few months later, Schridde (1912, p. 516) attempted to go further than 

 Ciaccio and Meves by claiming that the mitochondria diminish in number in 

 direct proportion to the increase in the hemoglobin, and, on the basis of this, con- 

 cluding that the plastosomes (mitochondria) are the formers of the hemoglobin. 



This was followed almost immediately by a second paper by Ciaccio (19136, 

 p. 393), in which he says that there is no foundation for Schridde's opinion. He 

 holds to his original view that the part played by the mitochondria is quite indirect. 

 His chief and only objection appears to be that the acid fuchsin, which J^chridde 



