CYTOPLASMIC INCLUSIONS OF THE GERM-CELLS 9838 
out between the time the sperm leaves the spermatic tubule, 
and enters the egg. 
Two suggestions are obvious and may be set forth: (a) Both 
mitochondria and Golgi apparatus are concerned with the 
production of the energy used up by the movements of the 
sperm tail. (b) Hither the mitochondria or the Golgi 
apparatus (or both) carry some active substance which is set 
free just as the sperm enters the egg, or after it has penetrated 
the egg, and whose function is related in some obscure way to 
the phenomenon of heredity. 
It seems to be established that every mammalian sperm is 
partly formed of mitochondria, and we may find that every 
such sperm has a Golgi apparatus. The experimental evidence 
which is necessary for the elucidation of the function of these 
two categories of cell inclusions within the structure of the 
spermatozoon would be very difficult to procure, and it appears 
to be very doubtful whether mere observation of the behaviour 
of these inclusions durmg fertilization will provide any con- 
clusive facts. 
Tt has been said that the animal spermatozoon is merely 
a much modified cell, and it has been shown in this paper 
that the remark is true to the smallest detail, for a sperm 
such as that of Cavia is a complete cell with nucleus, mito- 
chondria, Golgi apparatus, and centrosome. In one fact, 
however, the two gametes differ widely: While the nuclear 
matter (chromosomes) of both gametes is similar in quantity, 
the mitochondria and Golgi apparatus of the spermatozoon 
are infinitely less in quantity than those of the ripe ovum. 
Are we to look upon the presence of the mitochondria and Golgi 
apparatus in the animal spermatozoon as being merely of 
phylogenetic importance, and indicative of a period when the 
two gametes were equal in size and metabolic potentialities, 
or should we entertain the view that the mitochondria and 
Golgi apparatus are specially concerned with a ‘ cytoplasmic 
heredity ’, as apposed to a ‘ nuclear’ one ? 
It has never been shown satisfactorily that either the mito- 
chondria or the Golgi apparatus can originate from the nucleus, 
