700 GEOFFREY LAPAGK 



suggests that, either some of the cases cited above are correctly 

 interpreted as instances of endogenous bud(hng, or that, 

 alternatively, the Thecamoebidae are not so closely allied to 

 the Amoebae as has been thought. 



All these considerations shook my belii^f in the very attrac- 

 tive view that I was witnessing an epidemic of endogenous 

 budding. 



(3) Hypothesis of Cannibalism. 



Turning to the third alternative I found that the cannibalism 

 hypothesis not only explained those facts which the other 

 views explained, but explained them much more simply and 

 readily. In addition, it did not fail where the other two views 

 had failed. This hypothesis provides the simplest explanation 

 and it covers all the facts without introducing into the already 

 complicated problem of the life-history of amoeba a new and 

 hitherto unauthenticated process. 



Further, it explains simply enough how such structures 

 as those shown in PI. 28, figs. 1, 2, and 4, and PL 29, fig. 7, 

 can arise. These structures are explained m detail in the 

 text explaining the figures. It is sufficient here to say that such 

 structures arise by the ingestion by amoebae of other amoebae 

 which had previously themselves ingested yet other amoebae, 

 a process which can give rise to the most remarkable and com- 

 plicated structures. Such phenomena must be pathological. 

 Whether cannibalism itself is pathological is a matter of opinion, 

 in the present state of our knowledge. That it is not a frequent 

 occurrence is shown by the paucity of references to it in the 

 literature, although Doflem (9 a) says that he has often seen 

 cannibalism, i.e. the eating by amoebae of young forms or of 

 cysts of their own species, and that such occurrences have 

 given rise to statements about internal budding and formation 

 of embryos. 



An amoeba, in the absence of its normal diet, will eat almost 

 anything. In my omti cultures of Amoeba proteus, for 

 example, these organisms, which were thriving upon a diet 



