. The Journal of experimental zoology. ng of the division rate whichaffected all the cultures alike. This temporary check always dis-appeared when the temperature came back to the normal state. CONCLUSIONS Our experiments show that: 1. There is no evidence that alcohol acts as a periodic or con-tinued stimulus. 2. There is no evidence that the general vitality would decreaseunder the constant stimulus of minute doses. 3. Alcohol in minute doses, 2 per cent or less, has no effectwhatever. 4. When a medium dose is given, for example 3 per cent, thegeneral vitality is weakened. 5. If alcohol is g
. The Journal of experimental zoology. ng of the division rate whichaffected all the cultures alike. This temporary check always dis-appeared when the temperature came back to the normal state. CONCLUSIONS Our experiments show that: 1. There is no evidence that alcohol acts as a periodic or con-tinued stimulus. 2. There is no evidence that the general vitality would decreaseunder the constant stimulus of minute doses. 3. Alcohol in minute doses, 2 per cent or less, has no effectwhatever. 4. When a medium dose is given, for example 3 per cent, thegeneral vitality is weakened. 5. If alcohol is given in greater strength than 3 per cent therate of division is lowered and the organisms finally die. LITERATURE (i) Gary N. Calkins and C. C. Lieb 02—Studies on the Life-History of Protozoa. 2. The Effects of Stimuli on the Life-Cycle of Paramecium caudatum, Archiv fiir Protistenkunde.(2) LoRANDE Loss WooDRUFF o8—Effects of Alcohol on the Life Cycle of Infusoria, Biological Bulletin, vol. 15, no. 2, July. 2o6 W. A. Math en y ^ J CONTROL _. .-_1-10X __ .-1-25;^ ^ ..-1-50 >« _ 1 / O O O O 2 / • • ... ZV- A °A .... 5 % The ordinates represent theaverage daily rate of division. The figures below indicate thenumber of eight-day periods DIED Chart showing division rate of cultures averaged for eight day periods. THE CHROMOSOMES IN THE GERM-CELLS OF CULEX N. M. STEVENS Bryn Maivr CollegeWith Fifty-two Figures In the summer of 1905, Miss Boring and I collected materialfor the study of the spermatogenesis of the mosquito, but the germ-glands proved not to be sufficiently well fixed. In 1907 I spentseveral days studying aceto-carmine preparations from the larvaeand pupae of some California mosquitoes. Naturally I expectedto find one or more heterochromosomes, but nothing of the kindcould be detected either in the growth stages of the spermatocytesor m the maturation divisions. The number ot chromosomes wassmall, only three in one species and tour in the other, but it
Size: 1653px × 1512px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1910
