Gland-Cells of Internal Secretion in Spinal Cord of Skates. 23 
animals the average amount of granular material was much nearer the 
normal. 
In all the animals stimulated by pilocarpine the average per section 
in terms of unit granules was 17.7, a definite increase over the normal 
average of 10.7. Plate 5 shows a few cells taken from the pilocarpine- 
stimulated skates. Figure 19 is a photograph of a cell showing an 
early stage in the secretion process. The central mass of cytoplasm is 
filled with vacuoles which contain a precipitate of some sort. This 
precipitate is probably formed largely from disintegrating cytoplasm, 
and in its staining reactions it behaves very much as the ordinary un- 
changed cytoplasm. The nuclear material appears to be placed at the 
extreme periphery of the cell. This is partly due, I believe, to the very 
recent dissolution and disintegration of some of the peripheral cell 
cytoplasm. A region of disintegration may be seen to the right of the 
figure, just outside the nuclear masses. Figure 20 illustrates the man- 
ner in which the cells are sometimes filled with enormous vacuoles. 
Five large ones and several smaller ones are to be seen in this case. 
Huge vacuoles are not very common in Raia ocellata. In Raia punc- 
tata they are found more often, even in the unstimulated animals. In 
figure 21 is a cell with a large amount of granular material near it. 
Probably a great deal of this had been formed, however, before the 
animal was treated with the pilocarpine. It is very interesting to note 
how the granules are all scattered through that half of the spinal cord 
in which the cell is located. None of them are to be seen to the right 
of the central canal. This close association of the granules and the 
cell is good evidence that the granules are produced by the cell as 
against their being phagocytosed by the cell. 
ATROPINE STIMULATION OF THE SPINAL CORD. 
Atropine is an alkaloid whose effect upon gland-cells is directly the 
opposite of that of pilocarpine. It was, therefore, of importance to see 
what effect it would have upon these large cells of the skate and to 
compare these results with the results from the pilocarpine skates and 
also the normal control skates. 
The method of administering the atropine was exactly the same as 
that used in the case of the skates stimulated with pilocarpine. In this 
series of experiments, 9 skates were used; 3 of these were treated with 
atropine for 5 minutes, 4 were treated with atropine for 10 minutes, 
and the other 2 were treated with the drug for 20 minutes. As before, 
the amount of granular material was computed in terms of unit gran- 
ules per section. 
The combined average of all 9 skates was found to be 10.6 unit gran- 
ules per section. This was practically the same as found in the normal 
control animals. In other words, the atropine has no effect either in 
increasing or decreasing the amount of granular secretion. 
