RESPIRATION IN MAN 191 



the impressions of the first, second, third, fourth, and fifth ribs 

 and costal cartilages. These impressions are marked in two ways : 

 the part of the lung lying under the rib is less pigmented and is 

 grooved ; the zones corresponding to the intercostal spaces are 

 more pigmented and are elevated above the level of the costal 

 zones. To obtain such results, for these marks cannot be post- 

 mortem effects, the relationship of the upper lobes to the upper 

 ribs must have been stationary during life ; there could have 

 been no gliding of the lung across the ribs and spaces during 

 inspiration and expiration. But on the lower lobe, except for 

 an occasional impression of the seventh costal cartilage, at the 

 anterior angle, these costal impressions are absent ; the pigment 

 is evenly distributed, or if not, does not correspond to spaces. The 

 inference one draws is that the lower lobe glides beneath the ribs 

 during the respiratory movements ; there is not, as in the upper 

 lobe, a constant relationship between ribs and spaces. But it 

 must be noted, too, that the dorsal surface of the upper lobe does 

 not show these costal impressions ; here, too, there must be a 

 downward and upward movement, one which I had inferred to 

 take place before my attention was drawn to the costal markings 

 as a guide to the respiratory movements of the lung. When 

 dealing with the movements and mechanism of the ribs it will 

 become apparent that the lower lobe and the dorsal part of the 

 upper lobe are chiefly expanded by a diaphragmatic mechanism, 

 and the upper lobe by the upper five ribs. It must not be sup- 

 posed that these markings are to be found on the lungs of every 

 individual ; they are constant in the lungs of women, and their 

 frequent absence on men's lungs can be understood when one re- 

 members how many there are that obtain their chief inspiratory 

 expansion by a moderate use of the diaphragmatic mechanism 

 alone. Pleuritic sounds and pleuritic pains are most intense 

 over the lower lobe ; Fowler and Pasteur have recorded casec 

 of paralysis of the diaphragm where the collapse was confined to 

 the lower lobe. The upper lobe is always relatively larger in 

 women than in men, a result to be expected from their manner 

 of breathing. It is true that pleuritic friction can frequently be 

 detected over the upper lobe ; this fact must certainly be taken 

 into consideration, but it must be remembered that a localised 

 pleurisy has a powerful reflex influence on the respiratory muscu- 

 lature corresponding to that part, and it is therefore probable that 



