THE CUTICLE OF A NEMATODE- 299 



10.— A CASE OF INJURY AND REPAIR IX THE CUTICLE OF A 



NEMATODE. 



By J. BURTON CLELAND, M.D., Ch.M., and T. HARVEY .JOHNSTON, M.A., D.Sc, 

 Bureau of Microbiology, Sydney. 



A PATHOLOGICAL process may be defined as the reaction which 

 follows an injury with the object of limiting its extent or of repairing 

 the tissue. Our knowledge of pathological processes is almost 

 entirely confined to vertebrates. An instance of such a process in 

 the nematode worm, Ascaris suilla, of the pig, has therefore seemed 

 to us worthy of record. In this case the essential process at work 

 was reparative in the sense of compensation for a breach of the 

 cuticle ; in other words, we consider it to be of the same nature as 

 an inflammatory reaction in a vertebrate. 



OZJ au 



Amongst a number of specimens of Ascaris suilla obtained 

 from pigs in the Sydney district in whose intestines Gigantorhynchus 

 gigas was also present in considerable numbers^ were various 

 specimens showing small crateriform projections little bigger than 

 a pin's head, scattered irregularly over the cuticle. The number of 

 these projections would vary on an individual from several to 15 

 or 20, or even more. Each showed itself as a slightly raised ring 

 with a central depression, the appearance, in fact, suggesting that 

 some parasite might have attached itself at the centre forming the 

 small depression, while the reaction to this irritation produced the 

 slightly raised ring around. It naturally occurred to us that 

 possibly the injuries might have been inflicted by the Echinorhynchs 

 also present in the intestine. Unless the condition was due to 

 microbial agency it seems hard otherwise to account for it. 



The microscopical appearances presented are also interesting. 

 In the healthy part of the cuticle away from the lesion the following 

 layers may be noticed in a cross section of the worm in passing 

 from without, inwards : — 



1. Cuticle and Epidermis. 



{a) A thick outermost layer of the cuticle showing no struc- 

 tural details and forming a projecting layer externally, 

 slightly raised into ridges. 

 (b) A narrow layer rather more deeply stained than {a). 



