advice on vomitting kitten

[itsaknockout]

Hi we adopted 2 (1m,1f) kittens from the cats protection league yesterday (thursday) afternoon. We don't know their age but the vet thought about 4-5 months.They arrived at the rescue centre on Tuesday , were neutered, vaxed and chipped the same day .So they have had a pretty stressful few days!
This morning teh boy kitten ate a good breakfast and pooed, but around lunchtime just wanted to hideaway and wouldn't come out at all.about 8 oclock he vomitted a huge amount of undigested food (despite not having eaten at all) and since then has had 3 more vomitting sessions of clear fluid.He has done a week which was just a few drops and a poo which was very slightly looser than normal but not diahhorea.He won't touch a bite of food or a drop of water and must be getting dehydrated.We live in the sticks and there is no way of getting to the vet tonight.
Is there any way of getting fluid into him?

[RubbishMantra]

Do you have a syringe or pipette? You can administer liquid with one of these. It's important not to squirt it down the back of the throat, as could cause choking.

Put the tip of the syringe (without needle, obviously) between the back teeth, then dribble the water slowly into his mouth, carefully.

This explains it better.