202 



THE SPUTUM. 



mucous membrane. This merely causes anaemia of the mucous membrane, while 

 the secretion continues.] 



Modifying Conditions. If ice be placed on the belly of an animal so as to cause the animal 

 11 to take a cold" the respiratory mucous membrane first becomes pale, and afterwards there is 

 a copious mucous secretion, the membrane becoming deeply congested. The injection of sodium 

 carbonate and ammonium chloride into the blood limits the secretion. The local application of 

 alum, silver nitrate, or tannic acid, makes the mucous membrane turbid, and the epithelium is 

 shed. The secretion is excited by apomorphin,' t emetin, pilocarpin, and ipecacuanha when given 

 internally, while it is limited by atropin and morphia (Eossbach). 



[Expectorants favour the removal of the secretions from the air-passages. This they may do 

 either by (a) altering the character and qualities of the secretion itself, or (b) by affecting* the 

 expulsive mechanism. Some of the drugs already mentioned are examples of the first class. 

 The second class act chiefly by influencing the respiratory centre, e.g., ipecacuanha, strychnia, 

 ammonia, senega ; emetics also act energetically as expectorants, as in some cases of chronic 

 bronchitis ; warmth and moisture in the air are also powerful adjuncts.] 



Sputum. Under normal circumstances, some mucus mixed with a little saliva 

 may be coughed up from the back of the throat. In catarrhal conditions of the 



Fig. 149. 

 Various objects found in sputum. 1, detritus and particles of dust; % alveolar epithelium 

 with pigment ; 3, fatty and pigmented alveolar epithelium ; 4, alveolar epithelium with 

 myelin-forms ; 5, free myelin-forms ; 6, 7, ciliated epithelium, some without cilia ; 8, 

 squamous epithelium from the mouth ; 9, leucocytes ; 10, elastic fibres ; 11, fibrin-cast of a 

 small bronchus ; 12, leptothrix buccalis with cocci, bacteria, and spirochaetae ; , fatty acid 

 crystals and free fatty granules ; 6, hsematoidin ; c, Charcot's crystals ; d, cholesterin. 

 respiratory mucous membrane, the sputum is greatly increased in amount, and is 

 often mixed with other characteristic products. Microscopically, sputum con- 

 tains 



1. Epithelial Cells, chiefly squames from the mouth and pharynx (fig. 149), 

 more rarely alveolar epithelium and ciliated epithelium (7) from the respiratory 

 passages. They are often altered owing to maceration or other changes. Thus 

 some cells may have lost their cilia (6). 



The epithelium of the alveoli (2) is squamous epithelium, the cells being two to four times 

 the breadth of a colourless blood-corpuscle. These cells occur chiefly in the morning sputum in 

 individuals over 30 years of age. In younger persons their presence indicates a pathological 

 condition of the pulmonary parenchyma. 



