106 LABORATORY MANUAL OF GENERAL PHYSIOLOGY 



(j) breathing into a paper bag, (k) effect of running up and down stairs. 

 The subject must not watch the record. Identify all records. Cf . Haldane 

 and Priestly, "Respiration"; Wiggers, "Physiology," chapt. 24; Howell, 

 12th Ed., p. 682. The pneumograph was devised by Fitz, Jour. Exp. 

 Med., 1:677, 1896. 



2. Respiration Scheme (Harvard). — Central glass cylinder = thorax. 

 Ballon = lung. Surface of water = diaphragm. Left manometer = intra- 

 thoracic pressure. Right manometer = intrapulmonary pressure. 

 Right tube at top = trachea with opening (glottis). Left tube at top 

 when open represents a pleural puncture. With left upper tube closed and 

 right open (glottis) lower the bottle at left of apparatus and raise. 

 Repeat. Make a diagram showing pressure in manometers during normal 

 respiration. Open upper left (pleural) tube and repeat. Represent other 

 features such as forced breathing, coughing, etc. (cf. W. T. Porter, Am. 

 Jour. Physiol., 10: 42, 1904). For a discussion of intrapulmonary and 

 intrathoracic pressure see Howell, 12th Ed., pp. 689-690. 



3. Respiratory Exchange in the Frog. — Determine the volume of the 

 bottle provided to contain the frog. Close with a tight fitting rubber 

 with sealed outlet tube. Label the bottle with your name, date, and time. 

 With the Haldane Henderson gas apparatus determine the O2 and the CO2 

 after several days. Weigh the frog and express the respiratory exchange 

 per gram body wt. For procedure in gas analysis (cf. Cannon, Lab. 

 Course, p. 134). Compare with other animals (cf. Rogers, p. 257). 

 Half the O2 intake is through the skin while the CO2 elimination through 

 the skin is 6 times that from lungs. The frog absorbs about 47 cc. O2 

 per kilogram body wt. per hr. at 18.8 C. Cf. Joel, Zs. Physiol. Chem., 

 107: 231, 1919); Winterstein, "Handb. vergl. Physiol.," vol. 2 Zweite 

 Halfte, p. 915, 1924. 



4. Rectal Respiration in Dragon-fly Nymph. — The caudal part of the 

 alimentary canal constitutes a tracheal gill. Water is taken in and forced 

 out through the anal opening. Place a little carmine powder on the bot- 

 tom of a small dish containing the naiad in water. Observe respiratory 

 movements (underside of abdomen). Note movement of valves. Deter- 

 mine the rate. Bubble CO2 through water vigorously. Now note the 

 rate and force. Explain. Cut off the legs and place animal in a large dish 

 of water. Tap abdomen (with a glass rod) and observe propulsive action 

 of the rectal mechanism. 



Cut off head. Note rate, regularity and force of respiratory move- 

 ments. Cut off abdomen (just behind attachment of wing rudiments). 

 Repeat observations. 



Now insert point of scissors in anus and cut through upper abdominal 

 wall. Pin open alimentary canal in paraffined watch glass and observe 

 under binocular microscope or with lens. Note mass of tracheal tubes and 



