“The first effect of a cigar upon any one demonstrates that tobacco can poison by its smoke and through the lungs.”—London _Lancet_. “The action of the heart and lungs is impaired by the influence of the narcotic on the nervous system, but a morbid state of the larynx, trachea, and lungs results from the direct action of the smoke.”—Dr. Laycock, Professor of Medicine in the University of Edinburgh. Additional Experiments. Experiment 114. _To illustrate the arrangement of the lungs and the two pleuræ._ Place a large sponge which will represent the lungs in a thin paper bag which just fits it; this will represent the pulmonary layer of the pleura. Place the sponge and paper bag inside a second paper bag, which will represent the parietal layer of the pleura. Join the mouths of the two bags. The two surfaces of the bags which are now in contact will represent the two moistened surfaces of the pleuræ, which rub together in breathing. Experiment 115. _To show how the lungs may be filled with air._ Take one of the lungs saved from Experiment 110. Tie a glass tube six inches long into the larynx. Attach a piece of rubber to one end of the glass tube. Now inflate the lung several times, and let it collapse. When distended, examine every part of it. Experiment 116. _To take your own bodily temperature or that of a friend._ If you cannot obtain the use of a physician’s clinical thermometer, unfasten one of the little thermometers found on so many calendars and advertising sheets. Hold it for five minutes under the tongue with the lips closed. Read it while in position or the instant it is removed. The natural temperature of the mouth is about 98½° F. Experiment 117. _To show the vocal cords._ Get a pig’s windpipe in perfect order, from the butcher, to show the vocal cords. Once secured, it can be kept for an indefinite time in glycerine and water or dilute alcohol. Experiment 118. _To show that the air we expire is warm._ Breathe on a thermometer for a few minutes. The mercury will rise rapidly. Experiment 119. _To show that expired air is moist_. Breathe on a mirror, or a knife blade, or any polished metallic surface, and note the deposit of moisture. Experiment 120. _To show that the expired air contains carbon dioxid_. Put a glass tube into a bottle of lime water and breathe through the tube. The A liquid will soon become cloudy, because the carbon dioxid of the expired air throws down the lime held in solution.