20 Beport of the Billiarzia Mission in. Egypt, 1915 



the skin as an established fact, the measures to adopt for preventing 

 it are clearly given. First of all, infected persons should never 

 evacuate urine or faeces into water, for this is the only vi^ay in which 

 the latter becomes populated with the dangerous germs. If any 

 body of water can be shown to be safe from contamination, it must, 

 as a matter of course, be left out of consideration as a source of 

 infection. If water is likely to be, or is likely to have been, 

 contaminated, it should not be used for bathing, washing, or working 

 in before about two days have passed. But even here a certain 

 reasonable discrimination should be made. For in a large body 

 of (standing or flowing) water, e.g., the Nile, any germs are soon so 

 much dispersed that the possibility of picking up one or another 

 becomes very small and may be increased only by a very prolonged 

 contact with the water. Dangerous in the first place are small 

 bodies of standing water, both permanent and transitory, because 

 in these the germs cannot disperse." 



In the last edition of Mense's "Handbuch der Tropenkrank- 

 heiten " (1914) he claims : — 



" Besteht die Haut infektioii im Wirklichkeit (sie wird neuerdings 

 von immer zahlreicheren Autoren als wahrscheinlichen bezeichnet) so 

 ist zu beachten, dass eine Auto-Eeinfektioa auch bei Wannenbiidera 

 mogleich erscheint, wenn der Badende unter soost gunstigen Bediuoungen 

 (absicbtlich oder unabsichtlich) Eier iu des Wasser entleer." 



If cutaneous infection really occurs — latterly an ever increasing number of authors 

 mention such an infection as probable — it is worthy of note that auto-rciufection 

 appears to be possible also when taking baths indoors, supposing the batlier, other 

 conditions being favourable (either intentionally or unintentionally), voids the ova 

 into the water. 



Blanchard's views on prophylaxis are expressed in the following 

 passage from his " Traite de Zoologie Medicale " [34], 1899 : — 



" L'infestation se fait par les eaux de boisson, soit qu'on ingere 

 I'hote intermediaire lui-meme, et alors il s'agirait d'un inollusque 

 de petites dimensions, soit plutot qu'on avale la Cercaire nageant 

 librement dans I'eau. . . ." 



" On a suppose que le parasite penetrait dans I'organisme a 

 travers le peau et, par suite, on a interdit formallement les bains 

 de riviere cette interdiction ne nous semble aucunement justifiee ; 

 encore que nous ignorions les phases ultimes du developpement, 

 il y a<<r<^serieuses raisons d'admettre que I'Helminthe penetre 

 reellement par la voie que nous avons indiquee plus haut. C'est 

 done I'usage d'eau non filLree ou non bouillie qu'il faut rigoureuse- 



