ISOLATION OF THE ORGANISM 643 



the gonococci will be set free, and one of the characteristic appearances lost. 

 The film should be stained by methods which will differentiate the gonococcus 

 from other organisms likely to be found with it. 



In medico-legal cases it sometimes happens that pus dried on linen has to be 

 examined for the gonococcus. Heger-Gilbert recommends that in such circumstances 

 the material should be dealt with as follows : 



Cut out the piece of linen on which the pus has dried and lay it in a watch-glass 

 on a piece of filter paper which has been thoroughly saturated with slightly alkaline 

 normal saline solution. Cover with another watch-glass and leave for 15 hours. 

 Then apply the fine end of a pipette to the different parts of the linen and aspirate 

 gently. The formed elements in the pus are thus sucked up with a little fluid into 

 the pipette. Spread the fluid collected in the pipette on a slide, dry and stain as 

 already directed (vide ante). 



(b) Cultures. To isolate the gonococcus in culture the pus should be col- 

 lected during the first few days of the disease ; later, infection of the urethra 

 with other organisms will complicate the technique. It is best to sow stroke 

 cultures on plates of serum-agar or blood-agar and to aim at getting isolated 

 colonies. 



Note. In chronic gonorrhoea, when the discharge is reduced to a mere drop, the 

 best method of finding the gonococcus is to instruct the patient to pass his urine 

 on waking into a conical vessel, and to let it stand, adding a crystal of thymol as 

 an antiseptic. In a short time whitish threads of mucus or muco-pus are deposited 

 at the bottom of the vessel. Aspirate the deposit with a pipette and prepare films 

 as already described. This method cannot be applied ,to the isolation of the gono- 

 coccus, and if it be necessary to obtain cultures the urine must be collected in a 

 sterile manner in a sterile vessel, and a thread at once removed with a sterile pipette 

 and sown on serum-agar. It is sometimes useful to centrifuge the urine and examine 

 the deposit for the gonococcus. 



In cases of gonorrhoea of old standing when the pus contains very few gonococci 

 it often happens that the latter cannot be found. Neisser has shown that a local 

 or general stimulant, e.g. an injection of nitrate of silver locally or the consumption 

 of beer, leads in such cases to an increase in the amount of pus, and in this it may 

 be possible to detect the gonococcus. 



