69 



alternative, since there are undonbted endodermal structures to which 

 the function of digestion may be assigned, and if he will kindly turn 

 to p. 104 of my paper he Avill find the following: "Digestion and ab- 

 sorption are both performed by the liver caeca and apparently by them 

 alone". I do not see how I could have expressed my views with greater 

 conciseness and definiteness than this. Verily the rain falls both on 

 the just and on the unjust, and it would seem that it is not I who have 

 come "vom Regen in die Traufe". 



Again, speaking of the pigment granules of the midgut cells Herr 

 Schönichen says: "Es ist völlig unverständlich, wie McMurrich 

 aus der Unveränderlichkeit jener Plasmaeinschlüsse auf die Untaug- 

 lichkeit des Mitteldarmes zur Verdauung schließen kann". Truly it 

 would be inexplicable, if I had ever done so. My observations on these 

 structures were simply to ascertain if they were assimilation products, 

 for, if they were, then the "midgut" was probably absorptive in func- 

 tion, but if not, it did not necessarily follow that the gut was non- 

 absorptive. It is inexplicable to me how Herr Schönichen could so 

 misinterpret my statements. I say, "I concluded, therefore, that the 

 granules could not be assimilation products", but not a word of sug- 

 gestion that this should be taken as evidence of the "midgut" being 

 non-digestive. 



Again, Herr Schönichen says with regard to my experiments 

 of feeding with cochineal, that they showed "daß nur in der Umge- 

 bung der Lebermündung dieser Farbstoff von den Zellelementen auf- 

 genommen wurde, während im eigentlichen Darmepithel keine Spur 

 einer Tinction zu finden war". The latter part of this sentence is cor- 

 rect, but the first is not. I did not say that the cochineal was found 

 "nur in der Umgebung der Lebermündung" but that "in every instance 

 the liver caeca were strongly tinged by the cochineal". And further I 

 may add that it is not a question as to the absorption of the grains of 

 cochineal and their intracellular digestion ; I have not seen this even 

 in the liver caeca : it is a question of the solution of the carmine by 

 digestion and the absorption of the dissolved pigment, and even this 

 does not take place in the "midgut". 



And this brings me to the final point to which I wish to refer. 

 Herr Schönichen has apparently failed to perceive the force of the 

 argument from parasitic forms because he has failed throughout to 

 understand, notwithstanding my explicit statement, that I regard the 

 liver caeca as the organs of digestion. In the parasitic Isopods men- 

 tioned it is the "midgut" which becomes rudimentary, but the liver 

 caeca retain their importance or even increase it. 



Herr Schönichen, throughout his criticism, has been tilting 



