306 PROCEEDINGS OF THE ACADEMY OF [iMay, 



gestion, several intestines were injected with killing fluid, to see if 

 penetration of fluid from the lumen would cause processes toward 

 the coelome. The result is shown in fig. 7, A and B. Nothing 

 could be more convincing. The processes of the nucleus, and in 

 large measure all deviations from the spherical, or at least regularly 

 curvilinear outline, are to be regarded as due to fixation. The 

 latter are the forms found in the living cell, and they are the only 

 ones considered in this paper to be perfectly normal. 



bb. Structure. — Several authors have described more or less 

 minutely the structure of the nucleus in fixed material. In adult 

 cells after fixation it is filled with large granules of chromatin, be- 

 tween which are traces of linin. From one to many nucleoli are 

 always more or less distinct. In young cells the chromatin is not so 

 a])undant, as INIcMurrich figures, and as may be seen from figs. 2 

 and 3. With neutral fixations like formo-alcohol, oxychromatin 

 may be distinguished. 



V. Bambeke seems to l)e the only author who has hitherto studied 

 the nucleus in fresh material. From evidence furnished by the 

 distorted nuclei, he says: " L' etude des noyeaux etrires permet de 

 conclure a une consistance visqueuse des parlies constituantes du 

 noyau, notammuent des filaments nucleolaire et de la substance 

 intermediaire ; les nucleoles (nucleoles plasmatique) present ent une 

 consistance plus forte et resi stent d' a vantage aux causes de deforma- 

 tion ;" and again, " La maniere d'etre des filaments dans les noyaux 

 elrires semble indiquer que dans le noyau intact ils sout pelotounes 

 et non disposes en reticulum." All other authors who have 

 observed the deformed nuclei have drawn similar conclusions with 

 reference to its consistency. 



As may be observed from fig. 5, I have found tlie structure of 

 the fresh nucleus plainly alveolar, like that of the cytoplasm, 

 except that the alveoles are larger. The relative size may be seen 

 in figs. 5, A and B. Both are drawn at the same magnification, 

 the cell in A being much smaller than that from which the nucleus 

 in B is taken. The alveolar structure may by chance be preserved 

 by over-fixation, e. g., " osmication," to use Bolles Lee's term. 

 In neither the fresh nor this over-fixed condition are granules to be 

 seen; but they are brought out sharply by nearly all fixations when 

 the action is not so powerful. I see no way to account for the over- 

 fixed alveoles on any other hypothesis than that of Fischer, who 



