Pedigree Race of Paramecium without Conjugation. 121 



tained (0.10 per cent.-0.20 per cent.) but this ash appeared as 

 white particles and was probably silica. 



When I undertook to prepare a melanin from black rabbit hair 

 and black feathers I found that the pigment was very insoluble in 

 dilute (0.2 per cent.) sodium hydrate, and it was only after long 

 boiling, in some instances nearly a week, that solution was effected. 

 Of course this procedure altered the nature of the melanin molecule, 

 but the fact that was of chief interest was that the resulting product 

 contained between 2 per cent, and 3 per cent, of ash and that this 

 ash was chiefly iron oxide. I have recently observed that there 

 are probably at least two pigments in the darker colors of horse 

 hair, one of these being a melano-protein with a very low ash 

 content, and the other containing approximately 3 per cent, of 

 ash which is chiefly iron oxide. 



These pigments have been prepared in such a manner as to 

 preclude any iron entering through contamination, and inasmuch 

 as other pigments, prepared by exactly the same process, contain no 

 iron, or at most only traces, we must conclude that in some in- 

 stances melanins may contain iron as a part of the molecule, but 

 that all melanins do not contain iron. Perhaps in this instance 

 the oxidase acted on the hemoglobin, or some other iron complex, 

 instead of oxidizing a protein containing no iron. 



86 (695) 



A five-year pedigreed race of Paramecium without 

 conjugation. 



By LORANDE LOSS WOODRUFF. 



[From the Sheffield Biological Laboratory, Yale University.] 



The unicellular organisms afford a natural means of approach 

 to the problem of fertilization, and the study of data, from 

 a long series of careful experimental studies on these forms by 

 various investigators, has pointed to the conclusion that the most 

 important function of conjugation in the life history of the Protozoa 

 is a satisfying of an inherent periodic physiological need of living 

 matter, resulting in a renewal of the vigor of the cell. This 

 "dynamic" view of fertilization has gradually assumed a com- 



