SPECIAL FORMS OF CONJUNCTIVAL INFECTION 141 



Mixed infections due to the Koch-Weeks bacillus, with Gonococci 

 Pnciimoeocci, or Diplobacilli, are not common according to general 

 experience. No specially characteristic clinical features have been 

 noted in such cases, except in the case of the complication with 

 gonorrhoea observed so often in Egypt. Meyerhof on one occasion 

 found diphtheria bacilli along with them, and after the Koch-Weeks 

 bacillus had disappeared these others caused the formation of a slight 

 pseudo-membrane. Morax reports a Koch-Weeks infection as super- 

 added to the exanthematous irritation of the conjunctiva in an epidemic 

 of measles. The Koch-Weeks bacillus has a great tendency to occur 

 in trachomatous cases, when it presents the deceptive clinical appear- 

 ances of acute trachoma. In the epidemic recorded by Wilbrand, 

 Saenger, and Staehlin, the Koch-Weeks bacillus had often associated 

 with it Pseudo-gonococci i.e., Diplococci belonging to the group of the 

 Staphylococci. These are the very cases which various authors state 

 to be associated with follicle formation, and they call to mind the 

 follicular epidemic of Michel and Sattler. 



When the secretion diminishes, the specific bacilli rapidly disappear. 

 They may, however, remain latent for a long time when the powers of 

 resistance are low (Morax, Hofmann, Meyerhof). 



Concerning the vitality of the bacilli in the secretion, see under 

 heading ' Contagion,' p. 145. 



Cultures. 



The Koch-Weeks bacillus will only grow at brood temperature. Of 

 all the ordinary media the only one which is even occasionally suc- 

 cessful is very moist peptone agar (0'5 per cent.) of low alkalinity, and 

 then only when plenty of the secretion is taken. Only very few 

 investigators have thus succeeded in obtaining one generation (Morax 

 once obtained three), and prolonged cultivation is quite impossible. 

 Morax definitely states that cultures are only successful when very 

 virulent organisms are obtained from severe inflammations. Weich- 

 selbaum and Miiller did not allow of the identity of the organisms 

 which they had cultivated with those of Morax, because they could 

 not obtain growth on simple agar ; but Morax correctly pointed out 

 that their cases had been much milder. 



Generally speaking, some specially prepared medium is necessary. 



Morax, Weichselbaum, and Miiller found Wertheim's serum agar best (addition 

 of ascitic, ovarial cystic, or hydrocele fluid, etc.). On such media Morax obtained 

 100 generations ; Usher and Fisher obtained 50. Hofmann found Wassermann's 

 pig's serum nutrose agar useful ; later, he used a mixture of 2 parts weak glycerine 



