Morphology 



461 



This organism, therefore, presents itself as sufficiently meritorious 

 to maintain the field for the present. 



Morphology. — The organisms, as found in the sputum, occur as 

 very minute ovoid rods of about the same size as the influenza 

 bacillus. They measure approximately 1.5 fi in length by 0.3 /i in 

 breadth. They do not remain united as chains or rods, but separate 

 as individuals. They are somewhat pleomorphous, yet the varia- 

 tions are not considerable. Involution forms are not common. 

 There are no spores, no flagella, no motiUty. 



, Staining. — ^The organisms do not hold the stain well. Most of 

 the bacilU are pale, some contain uncolored areas or vacuoles. In 

 some cases the ends of the bacilli appear more deeply stained than 



Fig. 167. — The Bordet-Gengou bacillus of whooping-cough. Twenty-four 

 houTroId culture upon solid media containing blood (Bordet-Gengou). 



the middle. They do not stain by Gram's method, 

 recommend that the organism be stained with — 



The discoverers 



Toluidin blue s 



Alcohol 100 



Water ! . 500 



Dissolve and add 500 of 5 per cent, aqueous 

 carbolic acid. After two days filter. 



Isolation. — The organisms occur in almost pure cultures in the 

 whitish expectoration which escapes from the bronchi in the begin- 

 nmg of the disease. Later they become few and may disappear, 

 though the symptoms of the disease persist. 



Cultivation. — The cultures were secured upon a special medium 

 made as follows: 



I. Potato chips 1 1 B^ji ^^ „g the fluid. 



4 per cent, aqueous glycerin 2 J ' '^ 



II. Potato extract (made as above) . . 5° cc. 1 Boil, dissolve,' filter, and 



0.6 per cent, aqueous NaCl 150 cc. [ tube; 2 to 3 cc. to a 



Agar-agar S gm. J tube. 



III. To each tube add an equal volume of defibrinated rabbits' (or, better, 

 human) blood before cooling to the point of coagulation. Permit the tubes 

 to solidify in the oblique position. 



