732 THOS. H. MONTGOMERY, JR. 
INTRODUCTION 
This study was undertaken mainly to determine two questions 
that at present are of great theoretical importance, the mode 
of the conjugation of the chromosomes, and the origin and dis- 
tribution of the mitochondria: but I have found it necessary to 
investigate most of the other phenomena of the spermatogenesis 
at the same time, consequently I have been led to describe the 
entire spermatogenesis up to the ripe spermatozoon, thus com- 
pleting the investigation of this species begun by me in 1898.! 
Considerable time was given to the study of living cells, in which 
the testis was teased and placed in Ringer’s solution. It was 
a great surprise to me how much could be seen in this state: plas- 
mosomes distinguished from allosomes during the growth period, 
the mitochondria very distinct, in the maturation mitoses the 
centrioles and mantle fibers as clear as upon the best stained pre- 
parations and the chromosomes visible, though not so clear, and 
all the phenomena of the histogenesis of the sperm quite as dis- 
tinct as upon any stained preparations. By this intra vitam 
study a pseudopodium of the spermatid was found that could not 
be seen upon sections, and the stages in the shrinkage of the sper- 
matid nucleus be seen with the greatest clearness. This has 
convinced me that the fixed preparations we have all been study- 
ing present a very close picture of living conditions, provided a 
good fixative like Flemming’s stronger fluid isemployed. Despite 
what microchemists may conclude, we have been working with 
images that are very close to the living, and that may well be a 
source of great consolation. Indeed, the argument that cytolo- 
gists have for the most part studied only precipitates and coagu- 
lates need no longer be advanced to us, when structures seen in 
life so closely approximate those of fixed and stained sections. 
More than forty testes were sectioned after fixation by a variety 
of methods, though those fixed by Flemming’s and Hermann’s 
1 This is the species I have called E. variolarius Pal. Beauv. and a discussion 
of the identification is given in my paper 1910a. 
