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becomes of these cells ? Advancing further down the hind-gut, 
they apparently get fewer and fewer, and the faecal masses less and 
less mottled. It seemed to me unlikely that these living cells should 
be lost to the body, and I searched diligently to see if I could find 
any cells passing through the wall of the hind-gut. I found none 
actually passing through, but what I did find was almost more 
interesting in its suggestiveness. Between the fecal masses and the 
wall of the canal, round cells of granular protoplasm with a rather 
indistinct nucleus were found. These cells appeared in all the sections, 
some apparently just leaving the fecal masses. There can, I think, 
be little doubt that these cells belong to the places in the sections 
where they are found, and have not been swept-in in the processes 
of cutting and mounting. If so, there can also be little doubt that 
they are the representatives of the digesting cells which through 
overcrowding had broken loose and had been carried down into the 
hind-gut. These round cells within the hind-gut are quite indis- 
tinguishable from the blood-corpuscles in the blood-plasma outside 
the gut. W ithout making any positive affirmation, I think that it 
is highly probable that these digestive cells, instead of being lost to 
the animal by passing out with the feces, pass through the wall of 
the gut and function as blood-corpuscles. There seems no reason 
why this should not take place, although the actual fact would pro- 
bably be difficult to establish. 
This is, however, not the only interesting point in the digestion 
of Euscorpio. The peritoneal cells clothing the whole alimentary 
canal externally are found to be so full of globules, exactly re- 
sembling the typical food-globules, that both the nuclei and the cell 
divisions are entirely obscured. Bertkau found bodies somewhat 
similar to food-globules in the peritoneal cells of an Araneid ( Atypus ), 
but said that they differed from the latter in being built up of regular 
concentric layers, and further in their chemical reactions. While the 
typical food-globules, according to Bertkau (who, however, did not 
recognize them as such), are dissolvable in glycerin and water, but 
indissoluble in ether and alcohol, the bodies in the peritoneal 
cells resist the action not only of alcohol and ether, but also of 
water and glycerin. With osmium they are quickly and intensely 
blackened, and iodine makes them red-brown. Bertkau also found 
traces of these bodies occurring in the peritoneal layer of Eresus ; 
indeed there is reason for believing that they are very commonly 
present in the peritoneal cells of spiders (cf. next section). 
The homogeneous globules found in the peritoneal cells of 
Euscorpio show no traces whatever of lamination viewed under the 
highest power. They are in every respect indistinguishable micro- 
scopically from the food-globules within the digestive cells. So great 
is the similarity that it is difficult to believe that bodies so alike, and 
separated from one another only by the fine basement membrane of 
the digestive cells can be really different ; indeed, from what follows 
