They used to be thermal-vacuum switches- - - -used to turn emission controls and/or distributor vacuum advance or exhaust gas recirculastion valves on and off according to coolant temperature. Remove them and install pipe plugs instead if you want to clean up the cosmetics of the engine a little. Leave the bypass hose in place- - -it allows coolant to circulate through the block while the engine is warming up and prevents hot spots that could blow a head gasket or crack a cylinder head. If the proper thermostat is used, the bypass gets blocked off as the thermostat opens.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!