388 E. R. Downıng, 
N a 
100 1000 
The varying effects of different solutions are interesting, but have 
no bearing on spermatogenesis; the results also are yet very in- 
complete. 
It has been noticed by many observers that budding occurs 
when Hydra is well fed. Thus Laurent says „La production des 
bourgeons d’apres les observations de TREMBLEY et de tous ses suc- 
cesseurs, est fréquente pendant la belle saison chez les individues 
très bien nourris et nulle ou rare pendant l’arriéresaison surtout sur 
les Hydres qui se reproduisent par oeufs.” 
mals surviving in a KCl longer than others will in a N. 
Food. 
I have found also that during the spermatogenesis animals are 
nearly devoid of surplus food material. Figures will make apparent 
this difference. Fig. 14 is taken from a budding animal. It will 
be noted that both endoderm and ectoderm cells are filled with 
oranules, and distended with protoplasm. A layer of droplets 
staining intensely black with osmic acid occupies the peripheral 
margin of the ectoderm cells. Among the endoderm cells, too, appear 
certain granular masses, staining intensely with gentian violet espe- 
clally, which mark the gland cells. These are absent except during 
digestive processes. The ectoderm and endoderm cells are so full 
of granules, that it is extremely difficult to follow cell walls. The 
cells too are often multinucleate. Fig. 3 is taken from a Hydra on 
which testes were developed. The cells are not granular now, but 
the protoplasm even is so decreased that most cells are very vacuo- 
late. Having observed this starved condition repeatedly in sections 
of animals bearing reproductive organs it seemed possible that the 
absence of appropriate food might be the cause of the sexual repro- 
duction. So animals were kept without food for varying lengths 
of time up to three months, were fed sparingly on varioüs crustacea 
‘and oligochaeta, were alternately fed and starved, but all to no 
effect as far as the development of sexual organs was concerned. 
It was concluded therefore that the starved condition was an effect 
rather than a cause, and was due to the rapid use of nutritive 
material during development of ovaries and spermaries. These grow 
so rapidly that digestive processes can not keep pace. Food is 
seldom ingested during the sexual reproduction. 
It will be necessary to continue the experiments to determine 
