LIFE HISTORY OF THE LIVEK-FLUKE. 103 



During the summer of 1882 I at length obtained L. trunca- 

 tulus for my experiments, and succeeded in infecting them with 

 the embryos of F. hepatica. Before the end of August the 

 development of the species was obtained up to the time when 

 the tailed cercarise were nearly mature, and, as I had by me 

 well-preserved specimens of the rediae and cercarise found at 

 Wytham, I was able to compare the two forms step by step, 

 and see that they were identical. A paper was drawn up for 

 the October number of the ^Journal of the Royal Agricultural 

 Society,' giving these results, and was sent to the printer on 

 Sept. 1st. A fortnight later it received a revision, which was 

 merely verbal, and the whole of the copies were printed off by 

 Oct. 2nd. 



Separate copies of the paper were received for distribution on 

 the 24th Oct., but the journal was not published until nearly 

 the end of the month. 



Inthemean time a paper by Professor Leuckart appeared in the 

 ' Zoologischer Anzeiger' for the 9th October. In this he stated 

 that he too had succeeded in rearing the cercariaof F. hepatica 

 in L, truncatul us, *'the only true intermediate host," and that 

 it had proved to be not the tailless form, but, on the contrary, 

 the third form mentioned above, which he had supposed early 

 in 1882 could have no connection with the liver-fluke. 



On the 19tli Oct. a resume of my completed researches 

 was published in 'Nature,' attention being called to the fact 

 that the cercaria of the liver-fluke was the one already dis- 

 covered by me in Dec, 1880, and described in April, 1881, as 

 probably belonging to F. hepatica, and that the necessary 

 proof had been furnished by myself, and also independently by 

 Professor Leuckart. 



II. Methods of Investigation, 



On commencing the investigation into the life-history of the 

 liver-fluke it was felt that where so many different molluscs 

 had been suggested as possible intermediate hosts, it was neces- 

 ,sary to examine the question anew, and not to be guided by 



