CYSTICEKCUS IN THE EYE. 127 



already suffered for ten months from remittent ophthalmia of the 

 right side, that at least five months must have elapsed since the 

 immigration of the six-hooked embrvo before the woman observed 

 this vesicle ; in that case five months are sufficient for perfect de- 

 velopment, which was certainly completed when the woman first 

 noticed the vesicle ; and, lastly, it is certain that if the space be 

 not too much limited the vesicle thus far developed increases ex- 

 tremely rapidly in size, as Leuckart and I can affirm by reference 

 to the rapid growth of Cystic. tenuicolUs. 



b. In the posterior chamber of the eye. — The consequences are 

 always the same as in a. I had myself had the opportunity of 

 seeing a case which was regarded as Cysticercus protruding for- 

 wards through the pupil ; but I could not ascertain this positively 

 either by the examination of the uninjured eye or by that of the 

 portion of the pseudo -formation removed by operation and sent to 

 me. Unfortunately, nothing could be discovered of hooks or 

 sucking discs, but on a large spot of the part removed the micro- 

 scope certainly showed granular structures, which disappeared 

 with acetic acid, but was not altered by caustic potash, and which 

 were analogous to the calcareous corpuscles of the Cestodea. I 

 must leave it undecided whether this had anything to do with a 

 Cysticercus. An undoubted case of the occurrence of Cysticercus 

 celluloses in this position is reported by Von Graefe (' Deutsche 

 Klinik/ No. 45, 1856 ; ' Sitzungs-bericht der Gres. fur wiss. Med.,' 

 August 11th, 1856). The Cysticercus lay upon the hinder wall of 

 the eye, and was so distinctly perceived by the patient himself 

 that he was able to draw the shadow which the animal produced 

 upon his retina. In this case the rapid development of the animal 

 at first was remarkable. 



c. In the vitreous humour. — The detection of Cysticercus in the 

 deeper parts of the eye in the living human subject has only been 

 possible since the introduction of the ocular speculum of 

 Helmholtz into surgical practice. It is necessary, however, to be 

 careful in these inquiries, and to know how to avoid illusions. 

 Dr. A, von Graefe was the first to recognise this parasite in the 

 vitreous humour of the living human subject, and he has most 

 kindly communicated what follows, at my request. " A mem- 

 branous cylinder of about one millim, with transparent mem- 

 branous walls, is observed in the retina, near the dingy, brownish 

 optic nerve ; it is directed forwards, so that it runs through the 

 vitreous body nearly in the direction of the axis of vision. In 



