1893. J 111 [Hyatt. 
the resulting daugliter cells remain fastened together forming- 
colonies as in Protozoa or masses of tissue as in Metazoa, or 
wliether they separate and become distinct autotemnons or distinct 
zoons the action is the same. 
The product of this autotemnic function in single cells has, as 
shown by the researches of Maupas, a cycle of transformations 
which are like those of an individual among Metazoa, although 
they may reach in some forms over six hundred so-called genera- 
tions and therefore include thousands of distinct protozoans. It 
is obvious to the student of bioplastology in reading Mau|)as's 
researches^ that this cycle among Protozoa Ciliata, is the equiva- 
lent of the cycle of the individual among Metazoa. Although he 
uses the word individual for the autotemnon, he does not speak 
of the successive forms as generations but as partitions, 
"bipartitions" being his usual term, showing clearly tliat he recog- 
nizes these are not generations like those of distinct successive 
zoons in ^Eetazoa. 
Maupas's researches show, as in fact he himself states, that there 
is a cycle of partitions produced from one autotemnon after con- 
jugation, when isolated and allowed to propagate by fission with- 
out the renewed stimulus of conjugation with others of different 
broods. The earlier successive partitions are incapable or at any 
rate do not show any desire to conjugate wuth their fellows. 
Each of his cultures of isolated autotemnons passed through these 
youthful or anaplastic stages, and then a series of metaplastic par- 
titions was developed in which the micronuclei became more 
numerous, and conjugation with other broods took place whenever 
it was permitted by the experimenter. 
In the generations immediately succeeding, these degenerative 
changes, both structural and physiological, took place in the par- 
titions which were distinctly paraplastic, although the cultures were 
maintained under conditions which precluded the supposition that 
these changes could have resulted from unfavorable, abnormal 
surroundings. The successive partitions then had gerontic trans- 
formations, lost their micronuclei, became much reduced in size 
and unable to conjugate with others with the usual normal results, 
and finally the external buccal apparatus was affected, reduced, or 
1 Recherches experimentales multiplication des iufusoires cilies, Arch, de zool. 
exper. et gen., ser. 2, v. 6, p. 165-277; ibid. v. 7, p. 149-517. 
