170 Finer Structure of the Glandula Submaxillaris 
The first form of cell was filled with very highly refractive granules 
(“ dunkle Zellen” of Erik Miiller) ; another kind of cell contained very 
transparent granules, with a refractive index about equal to that of 
the protoplasm (“helle Zellen” of Miiller). The third form of cell 
occurred least frequently and contained granules of low refractive power, 
the so-called “ ring granules.” Such forms were found in fresh sections 
of the gland taken from a rabbit after a fast of twenty-four hours. He 
employed various fixing reagents for studying stained sections. With 
alcoholic fixation he found that all three forms of granules had dis- 
appeared. With acetic acid the clear cells were destitute of granules, 
while the granules in the dark cells remained undissolved. After fixation 
in formalin and staining with Heidenhain’s iron hematoxylin, he was 
able to distinguish: two kinds of cells: (1) clear cells which contained 
only isolated granules; (2) cells, which in addition to granules, con- 
tained filaments comparable to the vegetative fibers of Altmann. 
More recently Gerhardt, 03, has observed the granule complexes of 
this gland. He made a study of the changes in the salivary glands 
which followed upon section of the secretory nerves and found these 
granular areas in a gland sixteen weeks after section of the sympathetic 
in sections hardened in sublimate and stained with iron hematoxylin. 
He noted the occurrence of groups of granule-containing cells around 
the intercalated ducts but offered no explanation as to their nature 
beyond the suggestion of a possibility of their being artefacts. 
Illing, 04, in an article upon the comparative anatomy of salivary 
glands regarded the submaxillary of the rabbit as a pure serous gland 
of the tubular variety. He noted a peculiar appearance in the structure 
of the gland in the fact that in each cell a border and a central zone 
could be distinguished: “In der Randzone erscheinen die Zellen vollge- 
pfropft mit Kornchen, wihrend nach dem Lumen hin die K6rnchen 
sich mehr und mehr lichten und immer sparsamer werden, bis sie nahe 
dem Centrum schhesslich vollstandig verschwunden sind.” 
MATERIAL-TECHNIQUE. 
In the preparation of a series of submaxillary glands, which might 
be regarded as representative of the different stages of physiological 
activity, pilocarpine was used to stimulate a flow of saliva. In each case 
the rabbit was deprived of food for a period of twenty-four hours prior 
to the administration of the drug. It was determined by experimentation 
upon several rabbits, that the greatest exhaustion of the gland appeared 
