Hello. I was wondering if anyone could help me with identifying the insignia on my grandfather's helmet. He was a doctor, as the medical cross on the front confirms, but I'm struggling to find any more info on the the side stencil. I'm not totally sure, but it appears to be a mortar and pestle behind the yellow lightening bolt and small star. I have been unsuccessful in finding the lightening bolt and star on their own as well. Does this look familiar to anyone? Thank you in advance for your help.