In this chapter we are discussing the liquid that comes out of a locust, a sort of locust 'blood'. In truth, though, locusts, like all invertebrates, have no real blood, but rather a fluid called hemolymph - a fluid that bathes the insect's body cavity and supplies it with nutrients, but does not carry oxygen and the like. It is not red like blood, but has a greenish tint, and it is almost entirely water.
The Question of Its Kashrus Status:
The question before us is what the status of this fluid is with regard to kashrus, following the approach of the Bartenura. It is worth noting that among the Rishonim there is a different understanding, according to which the discussion belongs to the laws of tumah and taharah and of hechsher tumah, but we will not deal with that here. We will focus on the approach of the Bartenura, which is the halachah according to the view of the Rema, and on the kashrus status of the fluid with regard to eating.
There are species of locust that are kosher and species that are not. Obviously, if the locust is kosher, the juice that comes out of it is kosher as well. The question concerns a locust that is not kosher: what is the status of the juice that comes out of it?
There are two sides to the question:
Perhaps the fluid is considered a form of locust blood, and therefore it is not kosher.
Or perhaps it is not food at all, and it is not even forbidden, since this is not blood but simply a fluid seeping out of the locust's body. After all, tears that fall from a lion's eyes are not forbidden to eat - they are not food, but they are nothing more than plain water. Is this case the same?
The Testimony of Rabbi Tzadok:
Rabbi Tzadok testified "al tzir chagavim temei'im shehu tahor" - the brine, meaning the juice that drips from a locust of a non-kosher species, is tahor, that is, it is not forbidden to eat.
The idea behind this: when locusts were prepared for eating, it was customary to salt them in order to preserve them. The salt draws out the moisture inside the locust, and this moisture drips off it. That is the "tzir" - a salty liquid that comes out of the locust. Rabbi Tzadok testifies that it is not forbidden and does not render other things forbidden.
The Version of the Mishnah Rishonah:
The need for this testimony stems from an earlier version of the Mishnah, known as the 'Mishnah Rishonah'. In the generations preceding the Mishnayos that we have, a codification of the official Mishnayos was made, and that collection was called the 'Mishnah Rishonah'. In that version we learned: "chagavim temei'im shenikhbeshu im chagavim tehorim - lo paslu tziran" - that is, if kosher locusts and non-kosher locusts are pickled together, the brine that comes from the mixture is not treif.
From this wording it emerges that we are dealing with a mixture of kosher brine and non-kosher brine, and regarding a mixture they said that as long as the majority is kosher, the majority nullifies the minority. But the implication is that the brine on its own would be forbidden.
To this Rabbi Tzadok comes and rules that it is not so: the liquid that seeps out of a grasshopper, even from a non-kosher species, is nothing more than liquid. It is essentially water, and it has no halachic status as a product derived from a non-kosher creature, even though the grasshopper itself is not kosher, since this is not blood or anything comparable to it.
In summary: The fluid that comes out of a grasshopper is not blood but hemolymph, which is mostly water. Although the first Mishnah implies that the brine of a non-kosher grasshopper is forbidden on its own and is permitted only through the principle of nullification in a majority, Rabbi Tzadok testified that the brine of non-kosher grasshoppers is pure - it does not carry the status of a product of a forbidden creature, and it is not forbidden to eat.