②Powdered solid medicines with a medicine spoon; lumps and dense metal particles with tweezers, into the test tube, the test tube should be placed horizontally, the medicine into the mouth of the test tube, and then put the test tube slowly vertical.
3 liquid medicines should be taken care of: reagent bottle cap removed and placed upside down on the table, pouring medicines label toward the palm of the hand.
② saving principle: strictly according to the experimental dosage of drugs. If there is no indication of the amount, generally take the smallest amount, one or two milliliters of liquid, solid as long as the bottom of the test tube covered.
I hope I can help you solve your doubts.