762 



boundaries but remain distinct, except so far as the junction of the 

 nuclear matter unites them. In this case, at any rate, physiological 

 specialization has not rendered nuclear conjugation impossible. That 

 hunger or starvation of the cells is the direct cause of these epi- 

 demics of conjugation amongst the nuclei of the cells of the intestinal 

 epithelium of land-Isopods, appears very probable, but of this we are 

 not entirely certain. This process of nuclear conjugation differs from 

 all others hitherto described, 1) in that the cells maintain their 

 boundaries; 2) in that it occurs in a finished functionally active, 

 adult tissue; 3) in that it is either reciprocal or proceeds on the part 

 of the nucleus of one cell only; 4) in that it is not constantly con- 

 fined to a pair of cells but may affect or involve three; and that 

 5) two such nuclei may finally be found, without any apparent pre- 

 liminary action other than that one of these has wandered from the 

 cell to which it originally belonged into its new position alongside the 

 nucleus of another cell, without necessarily fusing with the latter. 



The apparently anomalous and altogether unique character of the 

 phenomena here described has led us to think that publication of the 

 facts might lead to further observation and experiment on the part 

 of others. The bearing which these facts have in relation to the pro- 

 cesses of the conjugation of the nuclei of sex-cells may at first seem 

 to be somewhat remote, but that they have a significance of that kind 

 seems not unlikely. They at any rate very positively prove that a 

 purely nuclear conjugation, not necessarily sexual, is not impossible 

 between the nuclei of adjacent cells forming part of a highly speciali- 

 zed tissue, such as in the epithelium here under consideration. 



It is known that ova are sometimes produced in the ovary of 

 certain animals by the fusion of cells or by a kind of phagocytosis, 

 but the phenomena here described cannot be considered as phagocytic; 

 nor can they be regarded as karyokinetic, since, as before stated, there 

 appears to be no evidence of destruction or assimilation of one nucleus 

 by the nuclear substance of another during this process of conjugation. 

 There are very manifest evidences of the disturbance of surface-tension 

 of the nuclei where they become amoeboid as in Fig. 1, which also 

 signifies that there have been corresponding chemical changes in the 

 surrounding cytoplasm of the cell, which is often much vacuolated. 

 The range of opportunities for conjugation between the nuclei of any 

 two pairs of cells of the intestine of Porcellio is considerably greater 

 than one would be at first inclined to suppose, since the cells of the 

 intestine are in rows in eight directions; namely, two transverse, two 

 longitudinally, and four diagonally, starting from any one cell as a 



