112 LECTURES. 



of their mode of development ; although, had I 

 sufficient time and opportunity at my command, a 

 discussion of this kind might be offered with very 

 great advantage. In my large illustrated work I 

 have devoted some six or more pages to purely prac- 

 tical matters connected with the presence of Ascaris 

 lumbricoides in the human subject, but the compa- 

 rative infrequeucy of the occurrence of this entozoon 

 in England renders it less incumbent upon me to 

 add to the details I have there given. Then again 

 as regards the Ascaris mystax, which I had the 

 good fortune first to recognise as a possible member 

 of the human parasitic fauna, so to speak, only some 

 half dozen cases have been observed and placed on 

 record. In British practice, I repeat, you will 

 rarely meet with cases of Ascaris lumbricoides i.e. 

 of Lumbrici, or Roundworms, as they are more 

 frequently called. When you do meet with them 

 they are not difficult to manage, and it is only very 

 rarely that more than one worm is present. Occa- 

 sionally, especially in hospital and dispensary prac- 

 tice, you will find several of these parasites occupy- 

 ing the same bearer, and only last year Mr. De 

 Morgan had a patient at the Middlesex Hospital 

 from whom as many as thirty-seven were expelled. 

 As a rule the presence of ascaris in the human sub- 

 ject is not detected before the patient has passed a 

 worm either by the mouth or anus ; but I have known 

 of one or more instances of successful diagnosis 



