144 E. PERRONCITO ON THE ENDEMIC DISEASE OF THE 



tween the 6 dpg. anteriorly and the f posteriorly appear the repre- 

 sentatives of the papilla which are found laterally in the perfect 

 Dochmius duodenalis. 



At first the body of the larva is not perfectly adapted to the 

 capsule ; between the one and the other is a vacant space which 

 sometimes diminishes by degrees, so as to succeed in being better 

 adapted, especially at the two extremities of the body. After from 

 one to two days, their skin separates from the salts of chalk (par- 

 ticularly from the carbonate of chalkj which, at first under the form 

 of granules, and after of corpuscles, shining, rounded, rectangular, 

 become one with the capsule. Thus this becomes always more- 

 rigid and friable, is sometimes easily broken by the movement of 

 the capsuled larva or in manipulating the preparations. At other 

 times it constitutes a protecting cuirass that resists rather strong 

 pressure. 



Arrived at this point, the calcified capsule is easily dissolved by 

 the gastric juice and by dilutions of chloridic acid without producing 

 efi'ervescence, and thus is set at liberty the beautiful larva, of yellow 

 colour, full of life. But its development stops here, and its death is 

 inevitable, unless it be carried into the human organism. The cap- 

 suled larvse resist a desiccation of 24 hours, and with the addition 

 of liquids, indiff'erent to preparations allowed to dry for that lapse 

 of time, they were seen to revive and become gradually as lively as 

 before. This particular resistance of the mature larvae to pro- 

 tracted desiccation demonstrates how the capsules containing 

 the living parasite can, by their great fineness and resistance, 

 be sometimes transported by the wind to a great distance, with 

 the dust suspended in the air, and infect localities previously 

 healthy. Once that the larvse are mature, or nearly so, that 

 is, capsuled, they live in limpid or in muddy water, explaining 

 thus an infection even to a distance with the translation of living 

 larvse. In waters containing little albuminous material or chalky 

 salts, I kept some that were most lively for more than 17 

 days after the incapsulation. The intensity of the infection from 

 waters containing them is shown in my own preparations, in some 

 of which in less than one drop of liquid more than a hundred mature 

 larvse might be counted. After two days of desiccation, by adding 

 water, I obtained the return of the larvje to their normal physical 

 state ; but though I warmed them to the proi)er point, there was 

 only in one any signs of vitality. 



