Velocity of conduction of impulses in rat myometrium is graded with dosage of estradiol cyclopentyl propionate. A single dose of the hormone was given and allowed to act for various periods of time before the animals were killed. Uteri from castrate control animals did not conduct impulses. The earliest effect of the hormone was seen 2 hr after injection, at which time an impulse was conducted with a velocity of 1.25 cm/sec. Velocity increased until 72 hr postinjection when it was 4.65 cm/sec. Uteri from rats 9 weeks postinjcction still conducted impulses at 3.51 cm/sec. Impulses travel on pathways that may be functionally discrete, though one pathway can excite another. Impulses also travel at different velocities on different pathways and it appears that there are bundles of longitudinal muscle fibers directly opposite the mesometrium that conduct faster than adjacent bundles. Pathways must sometimes be facilitated in order for impulses to travel the full length of the uterine horn.

A relatively simple technic for the intraspinal inoculation of mice which lends itself to routine laboratory use has been described. For Lansing poliomyelitis virus, it seems to be a more sensitive method of detecting virus than the intracerebral technic. The quantitation of virus titers by this method is consistent between two different technicians and on re-peated tests by one technician from anyone i set of virus dilutions. It can be applied to the routine testing of serums for Lansing antibodies. The chief advantage of the technic is the marked shortening of the incubation period of Lansing infection in mice as compared to that following intracerebral inoculation.

No abstract

No abstract

No abstract