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SCIENCE 



[N. S. Vol. XLII. No. 1080 



also, break loose from the globule. In tbe 

 free condition they become indistinguishable 

 from the free bodies which are abundant in the 

 cells of amphibian embryos and which are 

 ordinarily regarded as pigment. These pig- 

 ment granules, although having a color of 

 their own, at least upon their surface, stain 

 deeply with neutral red. The beta bodies give 

 the reaction for fat with Herxheimer's method. 

 That the beta bodies can not be degeneration 

 products in the strict sense is evidenced by the 

 fact that yolk globules remain intact for a 

 long period in dishes of putrefying embryos, 

 and that, in this condition, they do not stain 

 selectively in neutral red and nothing like beta 

 bodies can be found upon them. However, 

 such globules, taken from disintegrating em- 

 bryos, after they have been ingested by large 

 protozoa, stain selectively in the food vacuoles 

 of the living organism. In fact, large eiliates 

 which have been feeding in dishes where em- 

 bryos are disintegrating in a solution of neu- 

 tral red, become gorged with deep red granules 

 in dense masses. In one instance I have seen 

 a swimming ciliate discharge a niunber of 

 these granules, apparently as dejecta. 



In the study of the reaction to janus green 

 of yolk globules that have been ingested by 

 protozoa I have met difficulties which have not 

 been entirely overcome, but in one large ciliate 

 I have succeeded in getting the reaction of two 

 food vacuoles to the double stain of janus 

 green and neutral red. In this case the sur- 

 face of the globule stained a dense red and the 

 other contents of the vacuole around the yolk 

 globule a faint blue which changed in time to 

 faint pink. The latter reaction was delicate 

 but unmistakable. 



A study of the artificial digestion, also, of 

 yolk globules which have been taken from 

 dead embryos supports the view that the selec- 

 tive staining of yolk globules and the bodies 

 on their surface is due to processes of diges- 

 tion. When such globules are digested in a 

 mixture of pancreatin and neutral red many 

 stain selectively and bodies appear on their 

 surface which resemble beta bodies in living 

 preparations. With prolonged digestion in 

 pancreatin and neutral red the solution be- 



comes yellow, and the core of the digesting- 

 globules yellow, while the bodies on their sur- 

 face are deep red. Such reactions do not 

 occur in digestion with pepsin in solution with 

 neutral red, either with or without the addition 

 of hydrochloric acid, although there is positive 

 evidence of digestion in the mixture. Diges- 

 tion with pepsin and janus green, however, 

 brings about selective staining of globules 

 which, during digestion, break up into very 

 small bodies. These bodies stain a deep blue- 

 or blue-green. Such bodies occur, also, upon 

 the surface of more faintly stained blue glob- 

 ules, in which case they resemble the alpha 

 bodies of living preparations. Although they 

 are usually larger than the typical alpha 

 bodies, some of them are of about the same 

 size. 



In preparations of living cells stained with 

 the double stain of neutral red and janus green 

 I have on several occasions found an individ- 

 ual globule which had both alpha and beta 

 bodies attached, the alpha bodies situated in 

 bluish areas and the beta bodies in regions of 

 fainter red. One such globule I had under 

 observation for over eight and one half hours. 

 During the latter part of this period beta 

 bodies became detached from the globule 

 while the globule became much reduced in size- 

 and retained the bluish tint over a relatively 

 larger area than formerly. During this time 

 an alpha body, also, disappeared from the 

 surface of the globule, but it could not be 

 recognized afterwards in the free condition as 

 were the beta bodies. The latter, in the free 

 condition, assumed the characteristics of the 

 so-called pigment granules in the same prep- 

 aration. 



These preliminary observations have left a 

 strong conviction in my mind -that, in the 

 digestion and assimilation of yolk in these 

 embryos, enzymes effect a cleavage of the super- 

 ficial substance of the globule; that, following 

 this cleavage, the end-products of the process 

 segregate into alpha bodies on the one hand 

 and beta bodies on the other, and that the 

 alpha bodies, probably undergoing some 

 chemical change in the meantime, become free 

 as mitochondria in the process of assimilation 



