MESOTZNIUM, AND SPIROTANIA. 209 
as I regard it, we must suppose that this takes place when 
the plant has reached the end of its existence, and has arrived 
at the ultimate stage in its history—that is when it is at 
maturity—each of the conjugating pair of cells surrendering 
individual existence in giving origin, by the union of their 
contents, to the spore from which is to be evolved the 
primordial individuals of the next generation. 
And this leads to an important point in the argument, 
bearing on the difference of opinion between Dr. Hicks and 
myself on the matter immediately in question—I mean, the 
value or import to be attributed to the conjugative act, as to 
which point I feel bound altogether to agree with Professor 
de Bary.* 
Dr. Hicks considers it “merely an act of fusion ”— that is 
certaily a brief but true definition of the simple act in itself; 
but it is not the modus operandi of the mere act that is in 
dispute, but the physiological significance or import of that 
act. From his saying that is “merely an act of fusion, not 
of impregnation,”+ I infer that he conceives that it has no 
special significancy. But can a phenomenon which has been 
going on for years and years uncountable, since Conjugate 
were—restricted, with a few exceptions, as it is, to the group 
so denominated, and the Diatomaceze—be simply accidental, 
and quite devoid of all significancy? I cannot believe it 
reasonable to suppose that it should be so. 
I believe that the phenomenon of conjugation can be re- 
garded as nothing less than an indication of a distinction 
between germ-cell and sperm-cell, the humblest manifestation 
(it may be) of a difference of sex, which becomes by degrees 
more and more forcibly pronounced in the higher organisms, 
yet in none more firmly established, nor more conclusively 
settled, and that by direct observation, than in some of the 
lower Algze, which, by reason of their simple structure, range 
themselves (along with the Conjugatz) in the group of Con- 
fervoidee. It may be urged, indeed, that the conjugating 
cells show no so great differentiation either in organization, 
dimensions, or appearance, as do the spermatozoids of those 
Algze in which they have been discovered, from the germ- 
cells which it is their function to fertilize. This to a large 
extent is granted; but, nevertheless, a certain amount of 
specialization of certain conjugating cells in some forms does 
occur, pointing to something more than a mere fusion, with- 
out any significance. Indeed, the conditions which accompany 
She 
* Untersuchungen tiber die Familie der Conjugaten.’ 
+ ‘Quarterly Journal of Microscopical Science,’ N. S., Vol. I, p. 18. 
