Here is how Soncino translates the passage:
Our Rabbis taught: One should not drink water in the night; if he does drink his blood is on his head, for it is dangerous. What danger is there? The danger of Shabriri. But if he be thirsty, how can he put things right? [DB: What's his remedy?]— If there is another person with him, he should wake him and say: 'I am athirst for water'. If not, let him knock with the lid on the jug and say to himself: 'Thou [giving his name] the son of [naming his mother], thy mother hath warned thee to guard thyself against Shabriri, briri, riri, iri, ri, which prevail in blind vessels.'Soncino's notes provide the following interesting bits of information:
- Shabriri is usually taken as Hebrew for "breaker of the eyesight." Kohut (I presume either Alexander or his father Jacob) says the word is actually shab-khiri which is Persian for "night blindness"
- The spell, Soncino notes, works just like the abracadabra amulet, a Roman charm which proposed that the power of a disease or demon could be reduced if a letter of its name is reduced on each mention until only one letter remains.
So now what? My position is that this passage means only to share a bit of wisdom and good advice, and neither the demon nor the counter-charm should not be understood to have any efficacy; also the passage should not understood to have any Mesoratic value. The Rabbis lived among people that believed in demons and spells naturally came to believe in them, too. Their information on such non-halachic subjects such as demons and spells was not infallible, as it was entirely based on the excepted knowledge of their own time and place. In this case in particular, it seems apparent that the demon is a Persian invention, with a Persian name, and the remedy a common pagan solution. This is a conclusion, by the way, that is perfectly appropriate for a believing Jew to accept. As Samson Rephael Hirsch explained:
Our Sages were the scholar of the divine religion and were the recipients, transmitters and teachers of God's guidance, ordinances, commandments, and statutes; they were not especially natural scientists, geometers, astronomers, or physicians except as it was necessary for their comprehension, observance and performance of the Torah - and we do not find that this knowledge was transmitted to them from Sinai...[their] sagacity is in no way diminished if in another generation it is determined that some of his statements, in making which he had believed and accepted the reports and investigations of others, were based on incorrect premises.
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