C. RESPIRATION 



I. RESPIRATK .\ KV LUNGS. 



289. l\'cspinitiou scheme. Study the mechanics <>f mammalian 

 ie-piratioii in the artificial respiration scheme, following the descrip- 

 tion given in the Harvard Apparatus Company C'atalogue, p. 74. 

 The manometer- -hoiild he tilled with distilled water and the prc-- 

 sure condition >hi nld he such that the lung is alwav- -lightlv 

 stretched even in expiration. This i> done hy closing the cavity in 

 the ]>leural tuhe with the water level near the lung. 



Xote especially the following: 



a. I're-siire relations in thorax and lung cavities during inspira- 

 ti n (lowering water level) wtih tracheal tuhe open. Same dur- 

 ing expiration. 



1). Same as ahove hut with tracheal tuhe partially closed. l\ai-e 

 and lower the water level rapidly and note the effect on intrapul- 

 monic pressure. C"lo>e the tracheal tuhe more and more and note the 

 effect^ on intrapulmonic pressure. 



c. During ins])iration o]ieii the picural tuhe. Xote the effect 

 on intrathoracic pressure. This is what happens when a hullet 

 enters the chest. 



d. Coughing or sneezing and hiccough can he imitated in the 

 artificial scheme. 1 )o vou -ec how? 



II. <>xii)ATI()X [N THE TISSUES. 



-''/I. (iascs i/ircn off iii respiration. Fxpire through a gla-- 

 tuhe and I '.a ( < >H ), solution in a bottle. \\"hat does the precipitate 

 indicate;- To make sure that the O )_, is actually increased in expired 

 ;,ir arrange another bottle with the same amount of Ba(OH), 

 solution and draw air through it by inspiration the same number of 

 times as in the previous experiment on expired air. Which bottle 

 contain- the m>-t precipitate? 



Breathe against a cold plane pane of glass. What gas is indi- 

 cated? Is this an oxidation product? 



291. I ittlcpcinlcncc of C<). production mid ()._. consumption. 

 "Intramolecular respiration." ("arefullv remo\-e the seed-coats from 



' pra- that have been snaked in water over night. Fill a small vial 

 with mercury , and invert in a small vessel containing mercury, taking 

 care to admit no air. Xow place the peeled peas , me b\ one under 

 the rim of the \ ial s,, that they tloat to the top. Let stand one or 

 tuo day-, oh^i-rve the production nf gas. Test hv introducing 



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