HEART-BODY, ETC., OF CERTAIN POLTCH^TA. 267 



of the coelomic fluid cells; and Schaeppi found that in both 

 cases they resist the action of alkalies and cold acids. He there- 

 fore regarded them as consisting of chitinous chloragogen. 

 They gave no uric acid reaction. The cells of the intra-sinus 

 connective tissue, however, he found to contain guanin granules, 

 which, he suggests, are passed through the sinus wall into the 

 peritoneum, the cells of which he describes as falling off in 

 clusters from time to time. This process would give an 

 opportunity for the guanin granules to be carried into the 

 nephridia and excreted. With regard to the function of the 

 heart-body itself, on the other hand, he remarks that the 

 central position of the granules which occur in it, and the 

 absence of a secretory epithelium, are objections to any theorv 

 of glandular action. He considers that the organ, by swellino- 

 up at systole, owing to the pressure of the blood into its 

 meshes, acts as a valve. ^ 



' Some such mechanical function may very well belong to the organ, though 

 it seems unlikely that the blood should enter its meshes and swell it up ; 

 but still the presence of the chloragogen granules remains to be explained. 

 In the first place their material is evidently drawn from the blood ; but 

 though Schaeppi admits its excretory nature, yet lie objects on several grounds 

 to tlie inference that it is taking part in a blood-cleansing process. He 

 leaves the question in this dilemma, that the granules are neither accumulated 

 in the organ, for in old individuals it is often comparatively free from them ; 

 nor found in its periphery, as if in the course of being removed into the 

 body-cavity by leucocytes. Nevertheless the bulk of the evidence, and a 

 comparison with other animals, seem to point to the removal of the granules, 

 not necessarily intact, into the body-cavity, by a process similar to that which 

 Schaeppi describes for the guanin chloragogen of the intra-sinus connective 

 tissue. That there, in the ccelomic fluid, they or their debris should be 

 absorbed by the lymph-cells, the green granules of which are shown to have 

 the same properties, appears a natural theory. 



Schaeppi gives an account of the way the chloragogen granules of the small 

 lymph-cells fall into an alignment, fuse, and form the well-known rods which 

 characterise the Jarge lymph-cells. On account of their proximity to the 

 nucleus, however, he considers that the granules are originally derived only 

 from katabolic products of the nuclein ; which is equivalent to sayin" that 

 the admittedly excretory function of the rods, which it must be remembered 

 reach such a size as to be visible to the naked eye, is limited to dealiu"- with 

 the nuclear refuse of the single cells which contain them. Comparing the 



