33^ THE ANIMAL PARASITES OF MAN 



years old. Lutz also reports a successful experiment which must have 

 been positive, as the worms were expelled young. Finally, Epstein 

 conducted unimpeachable experiments on three children, which places 

 direct infection with embryo-containing eggs beyond doubt ; he, 

 moreover, proved that the development of the eggs takes place more 

 rapidly in the faeces when there is free admission of air, sun, and a 

 sufficiency of moisture. 



Accordingly, infection occurs partly through water, but princi- 

 pally direct from the soil. 



LITERATURE. 



CLOQUET, J. Anatomie des vers intestinaux. Paris, 1824. 



CZERMAK, J. Bau. . . . der Haut von Asc. lumbr. (Stzb. K. Acad. Wiss. 



math.-nat. Cl. Wien., 1852, ix., p. 755.) 

 RHODE, E. Beitr. z. Kenntn. d. Anat. d. Nematoden. (Zool. Beitr. [A. Schneider], 



1883, i., p. n.) 

 BENEDEN, E. van. L'appar. sex. fern, de 1'Asc. megaloceph. (Arch, de biol., 



1883, iv., p. 95.) 

 DAVAINE, E. Rech. sur le devel. . . . de 1'Ascar. lombr. (Compt. rend. Ac. 



sc., Paris, 1858, xlvi., p. 1217.) (Mem. soc. biol., Paris, 1862 [3], iv., p. 



261.) 

 HALLEZ, P. Rech. sur 1'embryol. et sur les condit. du develop, de quelques 



nemat. Paris, 1885. 

 LINSTOW, v. Ueber den Zwischenwirth von Asc. lumbr. (Zool. Anzg., 1886, ix., 



P- 525-) 

 GRASSI, B. Trichocephalus- und Ascarisentwickelung. (C. f. B. u. P., 1887, i., 



p. 131, 1888, Vol. in., p. 748.) 

 LUTZ, A. Zur Frage der Invasion von. . . . Asc. lumbr. (Ibid., 1887, ii., 



P.- 7 J 3-) 



LEUCKART, R. Die Uebergangsweise der Asc. lumbr. (Ibid., p. 718.) 

 LUTZ, A. Weiteres zur Uebertragung der Spulw. (Ibid., 1888, iii., p. 265.) 

 EPSTEIN, A. Ueb. d. Uebertrag. d. menschl. Spulw. (Jahrb. f. Kdrhlkde. N. F., 



1892, xxxiii., No. 3.) 

 NASSONOW, N. W. Z. Anat. u. Biol. d. Nemat., 2. (Arb. a. d Labor, d. zool. 



Inst. d. Warsch. Univ. f., 1897, P- J 33- Warschau, 1898.) (C. f. B., P. u. 



i. [i], xxv., p. 837.) 



GUIART, J. Role path, de 1'Asc. lumbr. (Arch, de parasit., 1900, iii., p. 70.) 

 SICK, C. Ueber Spulwiirmer in den Gallenwegen. Tubingen 1901. 



2. Ascaris canis, Werner, 1782. 



Syn. : Lumbricus cam's, Werner, 1782; Asc. teres,Goeze, 1782; Asc. cati 

 et caniculte, Schrank, 1788^ Asc. canis et felis, Gmelin, 1789; Asc. tri- 

 cuspidata et felis, Bruguiere, 1791 ; Asc. werneri, Rud., 1793 ; Fusaria 

 mystax, Zeder, 1800 ; Asc. marginata et mystax, Rud., 1802 ; Asc. alata, 

 Bellingham, 1839. 



The anterior end is somewhat recurvate, and provided with 

 lateral alar appendages, which give it the shape of an arrow-head ; 

 three almost equal lips around the mouth. The male measures 

 40 60 mm. in length, i mm. in diameter; the posterior end is 

 spirally bent and presents twenty-six pairs of papillae, of which five 



