14 Beport of the Bilharzia Mission in Egypt, 1915 



attempted to infect guinea-pigs by passing the Bilharzia eggs into 

 the stomach through a tube. They also injected the eggs into 

 the saphenous vein of rabbits, and also attempted to infect a 

 Macacus monkey by mixing large numbers of eggs- in its food. 

 These experiments were uniformly unsuccessful. 



Having convinced himself that the Bilharzia did not reqmre an 

 mtermediate host, Looss [288] attempted, in 1894, to infect monkeys 

 by the mouth. 



" Die Versuche wurden jetzt so angestellt, dass die ausgeschllipften 

 Einbryonen mit filtriertem Wasser ausgewasehen und dann in reines 

 ebenfalls filtriertes Wasser iibertragen und mit diesem an verschiedene 

 Tiere zum Trinken gegeben wurden. Mit dem Menschen selbst zu 

 experuTientieren, ging leider nicht gut an; as wurde, glaube ich in 

 Aegypten auch kein einwandsfreies Eesultat ergeben haben, denn fast 

 jeder zweite oder dritte Mann ist dort bereits von selbst infi'ziert Ich 

 benutzte deshalb Affen verschiedener Species, bei denen ja durcb Cobbold 

 ebenfalls das Vorhandensein einer Bilharz konstatiert wurde. Die Tiere 

 bekamen durch 6 und 8 Wochen bindurch taglich ein, zwei, teilweise 

 sogar drei Mai von dem stark embryonenhaltigen Wasser zu trinken 

 dasselbe wurde teils in gewohnlicher Temperatur, teils auf 37° c' 

 erwiirmt gegeben einer Temperatur, bei der sich die Embryonen 

 ausserordenthch lebhaft und agil zeigen— die spatere Untersuehun- (nach 

 8 und 10 Wochen) mehrever Affen ergab aber in alien Fallen ein durchaus 

 negatives Eesultat ! " 



The oxperiments were now carried out as follows : the freed embryos were washed 

 m filtered water and then transferred to clean, likewise filtered, water, and this was 

 given to various animals to drinlc. It was unfortunately impossible to experiment 

 with the human bemg ; and, indeed, in my opinion no incontrovertible results wouW 

 have been obtamable m Egypt by such a method, considering that practically everv 

 second to third person is already infected. I therefore employ monkevs of various 

 species, Cobbold having shown that a Bilharzia is found to occur in them. Du W 

 fromsix to eight weeks the animals were given some of this highly embryo -infectel 

 water to drink once, twice, and in some cases even three times a day ; the water was 

 given either at the ordinary temperature or at 37° C. the latter temperature being on 

 at which the embryos are found to be extremely lively and agile ; subsequent examina! 

 ton of several of the monkeys (after from eight to ten weeks) yielded in everf ase 

 absolutely negative results. "u iu e\eiy case 



Skin The hypothesis that an unknown larval staee 



Slo^r might enter the body through the skin had already 

 ,„ ,,, V ^een formulated in the Practitioner for 1888 bv 

 Allan [6], who wrote, " Nearly all the youths bathing m the Umzim- 

 dusi and Dorp Sprmt are mfected, while the girls, who do not bathe 

 remam free of the disease." In 1894 Brock [67] strongly supported 

 this view : My own inquiries have led me to the conclusion that 



