IX INTRODUCTION. 



A delicate layer of protoplasm derived from this plexus 

 surrounds the "brown body"*; and, indeed (according 

 to Joliet), the envelope which immediately incloses its 

 granular contents is formed at the expense of this layer. 

 It is from this protoplasmic covering, and not from the 

 substance of the " brown body " itself, that the bud 

 really originates ; the case therefore enters into the usual 

 order of development. In support of this view, Joliet 

 asserts that the bud is always separated from the " brown 

 body " itself by the membranous envelope, and is not 

 in connexion with its substance (Woodcut, fig. xxvi.) ; 

 but he adds, "// n'est certaintment pas toujours facile 

 de decider si c'tst aux depens du corps brun lui-meme ou 

 aux dSpens de cette couche protoplasmique que se forme 

 cette ' saillie de matiere granuleuse ' qui est Vorigine du 

 bourgeon," It certainly must be very difficult to decide 

 the point; and in the absence of any suspicion that 

 a tissue adequate to the formation of the polypide was 

 present in the neighbourhood, an observer would almost 

 inevitably refer the bud to the so-called germ-capsule as 

 its source. Joliet's researches, showing that the eudosarc, 

 by which the brown body is more or less surrounded, is 

 such a tissue, materially alter the case, and prove that 

 the appearances upon which I relied may possibly be 

 susceptible of a different explanation. At the same time, 

 I must add that the bud in the cases referred to always 

 seemed to me, after careful examination, to be directly 

 continuous with the " brown body," an uninterrupted 

 growth out of it, as represented in my figures. 



Secondly, what is the relation of RepiachofFs observa- 



* Killers hod previously described the " browji body" in Jf//]>r>j>//rel/a as 

 enveloped by a protoplMBlic substance, nj>. <-if. p. 119. 



