September 10, 1915] 



SCIENCE 



347 



two and two, by twenty-one lines, then any 

 seven planes that contain these twenty-one 

 lines will osculate a second cubic curve. 



Edwin Bidwell Wilson 



SPECIAL ARTICLES 



PRELIMINARY STUDIES ON INTRACELLULAR DIGES- 

 TION AND ASSIMILATION IN AMPHIBIAN 

 EMBRYOS ^ 



By means of a double stain of janus green 

 and neutral red in an isotonic salt solution, 

 the initial dilution of each stain being about 

 1:10,000, the yolk globules in the living cells 

 of Amblystoma embryos may be differentiated 

 into two types, which, for convenience of de- 

 scription, I designate as " alpha " and " beta " 

 globules. The alpha globules stain selectively 

 with janus green, at first greenish blue and 

 then pinkish, presumably upon reduction of 

 the dye. The beta globules stain selectively 

 with the neutral red, and are by far the more 

 numerous in the cell. When the same dyes 

 are used singly in a dilution of 1 :30,000 the 

 alpha globules are relatively inert towards the 

 red, and the beta globules are not stained by 

 the green. In smears of living embryos which 

 have been fixed upon the cover glass with the 

 acetic-osmic bichromate mixture and stained 

 with acid fuchsin according to the method of 

 Beusley,^ for mitochondria, the beta globules 

 stain a deep, brilliant red while the alpha 

 globules take on a duller tint, bordering on 

 purple. The two types of globules may be 

 similarly differentiated in sections prepared ac- 

 cording to this method. 



In smears of living cells which have been 



1 When this paper was written I was not ac- 

 quainted with the contribution of C. Saint-Hilaire : 

 ' ' Ueber die Veranderungen der Dotterkorner der 

 Aniphibien bei der intracellularen Verdauung," 

 Zoologische Jahrhiiclier, Ait. f. Allg. Zool. u. 

 Physiol., B. 34, Heft 2. After a careful study of 

 his results I am convinced that Saint-Hilaire has 

 not seen my ' ' alpha bodies. ' ' Otherwise, my ob- 

 servations, in many respects, are in striking agree- 

 ment with his. The differences in matters of inter- 

 pretation can not be discussed here. 



- Bensley, R. E., ' ' Studies on the Pancreas of 

 the Guinea Pig, ' ' American Journal of Anatomy, 

 Vol. 12, No. 3. 



stained in janus green, alpha globules may be 

 found here and there with deeply stained, blue 

 excrescences upon their surface. These struc- 

 tures may be described as " alpha bodies." 

 These are particularly distinct after the glob- 

 ule on which they occur has begun to take 

 on the pinkish tint. They frequently appear 

 as rows of slightly elongated masses connected 

 by slender threads of the same kind of sub- 

 stance. In optical section some of them seem 

 to dip into the substance of the globule while 

 others project in varying degree above it. 

 Some even have a very slight attachment to 

 the globule. In other instances similarly 

 staining substance is arranged in relatively 

 coarse bands with ragged outline, a condition 

 to which I shall refer again in considering the 

 toxic action of the dye. 



The different forms of alpha bodies I regard 

 as indicative of different stages in their 

 development. I have seen them in numerous 

 cases arranged in rows over the surface of the 

 globule as separate and distinct bodies. In 

 this condition they have the form and color of 

 mitochondria in the same preparation. In 

 one instance, in fact, after I had begun to 

 draw a globule with these separate and distinct 

 alpha globules on its surface, I observed that 

 some of the alpha bodies were changing their 

 position relative to each other, and, giving con- 

 tinuous and close observation to those bodies, 

 I saw some of them break loose from the 

 globule and become indistinguishable in form 

 and color from mitochondria which appeared 

 elsewhere in the same preparation. Alpha 

 bodies are visible also in smears and sections 

 made according to Bensley's method for mito- 

 chondria as noted above. 



Similarly there appear on some beta globules 

 structures which may be called " beta bodies." 

 These stain a deep red in contrast with the 

 more delicately tinted body of the globule. 

 In some respects they resemble in general 

 structure the alpha bodies, but they are of a 

 coarser nature. In some instances there is a 

 hull of this substance around the greater part 

 of the globule. Upon other globules it appears 

 in ridges or as a chain of angular bodies. In 

 smears of living cells I have seen beta bodies. 



