264 BULLETIN OF THE 



quiescent state from the influence of changes in the surrounding protoplasm. 

 The nuclear membrane and the " Protoplasmanetz " are functionally correlated, 

 inasmuch as the nutrition of the nucleus, which is impeded by the former, is 

 facilitated by the latter. This view agrees with the fact that both structures 

 are limited to extensively differentiated nuclei, 



Spengel ('76, p. 31, Taf. IT. Figs. 33, 35) calls attention in his paper on the 

 Urogenital System of Amphibia to a peculiar star-like figure which is occa- 

 sionally found to take the place of a nucleus in cells from the testis of Coecilia 

 rostrata. The "Stabchen" of this figure are stained in the hsematoxylin as 

 intensely as the nucleolus in other cases. Spengel thinks this appearance com- 

 parable with the process of nuclear division. Other structures, in form similar 

 to Chinese characters, are. often found in nearly all of certain groups or balls of 

 testis cells.* 



Flemming ('76) has communicated, in a paper devoted exclusively to the con- 

 sideration of the nature of the nucleus, the results of studies undertaken with a 

 view to determining whether the intranuclear network was present as a struc- 

 ture intra vitam. He made use of the urinary bladder of the salamander, and 

 operated on animals that had been poisoned by the injection of a solution of 

 curare, as well as on those which were not curarized. In both cases the tissues 

 remained in the same condition. 



With proper illumination it was possible to discern in endothelium, in mus- 

 cular fibres, in cells of connective tissue (Bindesubstanzzellen), and in nerve- 

 cells, this delicate intranuclear trestle-work ; but only in a few^ cases can its 

 connection with the nuclear wall be traced on all sides. The appearance is 

 often so blurred that one might, without exercising great care, be led to a be- 

 lief in the existence of only a granulation of the nucleus; the apparent granules, 

 however, are the optical cross-sections of the fibres of the continuous network. 

 Besides these apparent granules, there are present from one to three large nu- 

 cleolar structures, " Hauptnucleolen," and often smaller nucleoli, " Neben- 

 nucleolen," which differ from optical sections of the network in which they lie 

 by their greater size and different coloration or refractive power. In many of 

 the nuclei nothing of all this can be seen, but the results obtanied by the use of 

 reagents are proof that, in these cases also, the same structure is not wanting. 



By Hermann's method of analine staining still other structural differentia- 

 tions than those already mentioned may be demonstrated, — " Analinflecke." 

 These " Analinflecke " are not discrete corpuscles, but more intensely stained 

 portions of the network ; apparently they are only in part identical with the 

 nucleoli before mentioned, as they are far more numerous than the latter. 



In the discussion of the question, as to whether these appearances are due to 



* Perhaps the latter are of the same nature as the remarkable modifications which 

 the nucleus undergoes in certain cells of many invertebrates, especially Arthropods. 

 Compare in this connection the foUowing: H. Meckel ('46, pp. 33, 44, Taf. II. Figs. 

 26, 32, 33); Leuckart (Frey u. Leuckart, '47, p. 61, foot-note); Leydig ('57, p. 18, 

 Fig. 8); Chun ('76, p. 47, Taf. I. Fig. 5); Helm ('76, pp. 444, 458, Figs. 1-13, 

 55, etc.); and P. Mayer ('78, p. 42, Taf. I. Figs. 6, 9, 10, 11). 



