Bt stands for Bacillus thuringiensis which is a bacteria derivative that kills the looper caterpillars if they consume foliage on which it is sprayed. There are lots of Bt products including Dipel ...

And further, the same bacillus had been met with by Dr. Koch, a year previously, in the case of four patients who had died of cholera in India, and portions of whose intestines had been forwarded ...