Scientists at BioMed Valley Discoveries Inc., a division of the Stowers Institute for Medical Research, are using a century-old technique to eat away at cancer tissue found in inoperable tumors: bacteria. The scientists have been working with a bacteria that thrives in oxygen-poor conditions and that has been modified so that it doesn't produce certain toxins. They've found that when they inject it deep into tumors — where there is not enough oxygen for traditional therapies to work — the bacteria…