Lecturing is Easy, Teaching is Hard

Lecturing after a fashion is easy enough ; teaching is a very different affair. ... The transmission of ideas from one mind to another, in a simple unequivocal form, is not always easy ; but in teaching, the object is not merely to convey the idea, but to give a lively and lasting impression; something that should not merely cause the retention of the image, but in such connection as to excite another process, ' thought.'

 The Immune System Reaction and Overreaction

The body has a very ingenious and usually effective system of natural defence against parasites, called the immune system. The immune system is so complicated that it would take a whole book to explain it. Briefly, when it senses a dangerous parasite the body is mobilized to produce special cells, which are carried by the blood into battle like a kind of army, tailor-made to attack the particular parasites concerned. Usually the immune system wins, and the person recovers. After that, the imm...