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GENETIC REPRODUCTION. 97be essentially hermaphrodite. Conjugation under any circumstance is,however, interpreted by Engelmann as productive of a mere revitalizingor rejuvenating power, enabling the unicellular organism to continue itsnormal mode of multiplication by binary division. During all conjugativeprocesses, the disintegration and subsequent reconstruction of the endoplasticelement, and the assumption by the endoplastule of a striatedaspect, reported by Biitschli, is entirely corroborated.While inclined to acquiesce with the views of Engelmann and Biitschlinow briefly recorded, so far as their interpretation of the conjugative processis concerned, and, as previously intimated, to attribute to this processa chiefly revitalizing or rejuvenating function as implying the most logicalpossible interpretation of the reproductive phenomena exhibited by unicellularorganizations, the present author is not prepared to follow theseauthorities in that part of their argument which involves the disassociationof the endoplast with any function beyond that possessed by the nucleus ofan ordinary tissue-cell, or to deny to the Infusoria any faculty of reproductionbeyond that of binary division. The one alternative is mostintimately, and indeed inseparably, involved with the other, and in thisconnection sufficient consideration has certainly not been granted byBiitschli and Engelmann to the results practically, and not merelytheoretically, obtained by other workers in the same field. That theendoplast does, under certain conditions, exhibit phenomena entirelydistinct from those presented by the simple histologic nucleus, and thatthe Infusorial organism can propagate its kind by means other than thoseof simple fission, has been already demonstrated in the section devoted toexternal and internal gemmation, and is conspicuously manifested in suchtypes as Hemiophrya gemmipara among the Acinetidse, in which ramifyingdiverticula of the endoplast ascend into the anterior bud-like extensions ofthe body-substance and become separated off, and enclosed within the same,when the latter are severed from the parent organism ; phenomena ofan essentially similar kind are likewise presented by the gemmiparousAcineta mystacina and various species of the genus Spirochona. Thereis, further, no sufficient reason for doubting the accuracy of the observationsfirst made by Eckhard in the year 1846, and since confirmed andextended by Claparede and Lachmann, concerning the production ofinternal embryos in Stentor cceruleus and polymorphic, these embryos beingdeveloped individually from a single element or node of the characteristicmoniliform endoplast. Where such embryos have been reported, Engelmannand Biitschli have dismissed them as merely externally derivedparasitic forms, mostly Acinetae, referable to the genus Spkaropkrya ofClaparede and Lachmann, synonymous with Engelmann's genus Endosph(zra.Such in many cases they undoubtedly are, and notably in thosesupposed embryonic forms associated by Stein with the several typesStentor polymorphic, Bursaria truncatella, and Stylonychia mytilus /_. theseunmistakable parasitic forms represent, however, but a small and altogetherII