Experiment 197. _To examine connective tissues._ Take a very small portion from one of the tendons of a rabbit, or any animal recently dead; place upon a glass slide with a drop of salt solution; tease it apart with needles, cover with thin glass and examine with microscope. The fine wavy filaments will be seen. Allow a drop of dilute acetic acid to run under the cover glass; the filaments will swell and become transparent. Experiment 198. Tease out a small piece of ligament from the rabbit’s leg in salt solution; mount in the same, and examine under a high power. Note the curled elastic fibers. Experiment 199. _A crude experiment to represent the way in which a person’s neck is broken._ Bring the ends of the left thumb and the left second finger together in the form of a ring. Place a piece of a wooden toothpick across it from the middle of the finger to the middle of the thumb. Put the right forefinger of the other hand up through the front part to represent the odontoid process of the axis, and place some absorbent cotton through the other part to represent the spinal cord. Push backwards with the forefinger with just enough force to break the toothpick and drive its fragments on to the cotton. Experiment 200. _To illustrate how the pulse-wave is transmitted along an artery._ Use the same apparatus as in Experiment 106, p. 201. Take several thin, narrow strips of pine wood. Make little flags by fastening a small piece of tissue paper on one end of a wooden toothpick. Wedge the other end of the toothpick into one end of the strips of pine wood. Use these strips like levers by placing them across the long rubber tube at different points. Let each lever compress the tube a little by weighting one end of it with a blackboard eraser or book of convenient size. As the pulse-wave passes along under the levers they will be successively raised, causing a slight movement of the tissue-paper flags.