INCLUSIONS IN EGG OF ECHINAKACHNIUS 475 



2. Glycogen. As was mentioned formerly, no glycogen was 

 demonstrated in these eggs. No material was fixed by any of 

 the methods for the preservation of glycogen. 



3. Nutritive plates {yolk). V>y far the most conspicuous and 

 unusual inclusions are those which are best demonstrated after 

 fixation in Flemming without acetic, Meves' or Champy's 

 fluids, and staining in iron hematoxyhn or Benda's alizarin and 

 crystal violet. These bodies are shown in figures 1 to 6, 12, or 

 19 to 24. In figure 12, drawn from an egg fixed in Champy's 

 fluid, the}' are distinctly plate-like and much larger than in any 

 other lot of material. The more usual appearance is shown in 

 figures 19 to 24, where they are smaller and less distinctly plates. 

 Their fate indicates that they are nutritive in function. They 

 do not, however, respond to all the usual tests for yolk. At 

 first their staining reaction seems to mark them as mitochondria, 

 for in the series illustrated in figures 19 to 24 the fixation is 

 Flemming without acetic and they are stained a deep violet with 

 the Benda stain. They do not always give this reaction, how- 

 ever. The series described above was fixed for seven days. If it 

 be compared with the series shown in figures 4 to 6, which is also 

 Flemming without acetic, but fixed for eighteen to twenty-four 

 hours only, it will be seen that the large bodies are there in both 

 cases, but they differ in staining capacity. They take the violet 

 stain strongly after seven days' fixation, but are pink after one 

 day's fixation. The behavior of these two series when stained 

 with iron hematoxylin shows great dissimilarity also. In the 

 first case the plates are black and in the second they do not stain. 

 Since they are so striking in appearance in some series of eggs, 

 their apparent absence after other fixatives was unaccountable 

 until it was found that in practicall}^ every case the material of 

 which these plates are formed could be shown in the cytoplasm 

 even though not in the form of such distinct separate bodies. 

 For instance, when stained in iron hematoxylin after fixation in 

 modified Bouin, the cytoplasm had a decidedly reticular ap- 

 pearance with minute black granules throughout (fig. 18) ; in the 

 same material stained in Benda's stain (fig. 15), or in iron hema- 



