I think you’re thinking of Interstitium “ Meet Your Interstitium, a Newfound "Organ" These fluid-filled spaces were found in the body’s connective tissue” htt

I think you’re thinking of Interstitium “ Meet Your Interstitium, a Newfound "Organ" These fluid-filled spaces were found in the body’s connective tissue” https://www.scientificamerican.com/article/meet-your-interstitium-a-newfound-organ/ https://www.scientificamerican.com/article/meet-your-interst...