GENE TIC REP ROD UC TION. 



97 



be essentially hermaphrodite. Conjugation under any circumstance is, 

 however, interpreted by Kngclmann as productive of a mere revitalizing 

 or rejuvenating power, enabling the unicellular organism to continue its 

 normal mode of multiplication by binary division. During all conjugative 

 processes, the disintegration and subsequent reconstruction of the endo- 

 plastic element, and the assumption by the endoplastule of a striated 

 aspect, reported by Biitschli, is entirely corroborated. 



While inclined to acquiesce with the views of Engelmann and Biitschli 

 now briefly recorded, so far as their interpretation of the conjugative pro- 

 cess is concerned, and, as previously intimated, to attribute to this process 

 a chiefly revitalizing or rejuvenating function as implying the most logical 

 possible interpretation of the reproductive phenomena exhibited by uni- 

 cellular organizations, the present author is not prepared to follow these 

 authorities in that part of their argument which involves the disassociation 

 of the endoplast with any function beyond that possessed by the nucleus of 

 an ordinary tissue-cell, or to deny to the Infusoria any faculty of repro- 

 duction beyond that of binary division. The one alternative is most 

 intimately, and indeed inseparably, involved with the other, and in this 

 connection sufficient consideration has certainly not been granted by 

 Biitschli and Engelmann to the results practically, and not merely 

 theoretically, obtained by other workers in the same field. That the 

 endoplast does, under certain conditions, exhibit phenomena entirely 

 distinct from those presented by the simple histologic nucleus, and that 

 the Infusorial organism can propagate its kind by means other than those 

 of simple fission, has been already demonstrated in the section devoted to 

 external and internal gemmation, and is conspicuously manifested in such 

 types as HemiopJirya geininipara among the Acinetidas, in which ramifyino- 

 diverticula of the endoplast ascend into the anterior bud-like extensions of 

 the body-substance and become separated off, and enclosed within the same 

 when the latter are severed from the parent organism ; phenomena of 

 an essentially similar kind are likewise presented by the gemmiparous 

 Acineta mystacina and various species of the genus SpirocJiona. There 

 is, further, no sufficient reason for doubting the accuracy of the obser- 

 vations first made by Eckhard in the year 1846, and since confirmed and 

 extended by Claparede and Lachmann, concerning the production of 

 internal embryos in Stentor ccsrulcus and polyinorpJiiis, these embryos beino- 

 developed individually from a single element or node of the characteristic 

 moniliform endoplast. Where such embryos have been reported, Engel- 

 mann and Biitschli have dismissed them as merely externally derived 

 parasitic forms, mostly Acinetae, referable to the genus SphcErophrya of 

 Claparede and Lachmann, synonymous with Engelmann's genus Endo- 

 sphcera. Such in many cases they undoubtedly are, and notably in those 

 supposed embryonic forms associated by Stein with the several types 

 Stentor polymorpJms, Bursaria truncatella, and Stylonychia mytilus ; these 

 unmistakable parasitic forms represent, however, but a small and altoo-ether 



II 



