92 



the areas of hyperplastic connective tissue cells and some 

 thickening of the dense subcutaneous connective tissue. 



The following is the description of the microscopic 

 appearances of the conjunctival lesions observed by Lewis and 

 Seddon : — "From a study of the earliest lesions examined, 

 viz., those of Case I., the parasites appear to occur primarily 

 in lymph spaces. Only odd parasites or portions (in section) 

 are found apart from the necrotic material. The presence of 

 the parasites gives rise to small-celled infiltration as a tissue 

 reaction, followed by an aggregation of neutrophile leucocytes 

 and eosinophiles followed by necrosis of cells. While necrosis 

 is in progress around the parasites one finds at the periphery 

 of the mass large fibrous tissue cells massing together along 

 with giant cells. The tissue between the areas is composed of 

 typical granulation tissue, with eosinophiles and proliferation 

 of endothelial cells and fibroblasts. There is also in one section 

 some ulceration of the epidermis and some warty condition 

 of the epithelium similar to what is met with in other ulcer- 

 ative conditions." 



It will be seen from this description that the change is 

 essentially the same as that described above, varying mainly 

 in the degree of tissue reaction. 



The larval Nematode. — On account of the difficulty of 

 obtaining early lesions, few opportunities of minutely exam- 

 ining larvae have arisen. However, larvae have been 

 separated out from the tissues, and most of the important 

 characteristics have been determined. 



The method has been to separate the small necrotic areas 

 from the tissues of an early lesion. These have been softened 

 with pepsin or trypsin, washed, then lightly crushed between 

 two glass slides, dehydrated and cleared with carbol-absolute 

 alcohol. By gently moving and pressing the cover-slip placed 

 over the portion of crushed tissue, one has been successful in 

 forcing the larva out of the canal it occupies. The larva has 

 never been removed unbroken, but by piecing the broken 

 portions together the main external characteristics have been 

 clearly defined. 



As far as can be judged the larva is approximately 3 mm. 

 long by 40 /a to 53 /x broad. The anterior extremity tapers 

 slightly at the head, which is rounded. The mouth is sur- 

 rounded by thin prominent lips. The posterior extremity 

 tapers and terminates in a pointed tail, which is rounded at 

 the tip to form a small bulb furnished with minute spines. 

 The anus opens at about 83 ju, from the point of the tail. The 

 tail is curved rather sharply backwards. There are apparently 

 no transverse striations of the cuticle, but in sections fine 

 longitudinal ridges are seen. These longitudinal ridges are 



