270 Mr. E. A. Mincliin on the 



into a sticky matter. Bell (1, p. 565), like Jourdan, attri- 

 butes the elongation of the organs in our form to the unrolling 

 of a spiral thread of connective tissue. 



However well this explanation of the elongation as due 

 to the pressure of liquid may apply to Semper's Bohadschia, 

 and possibly also to //. catanensiff, It Is totally inapi)ricable 

 to H. nigra, and I believe also to H. impatiens. This Is 

 shown by the fact that in H. nigra an isolated Cuvierlan 

 organ can be made to elongate by itself. If In a living 

 animal one of the Cuvierlan organs be pricked or otherwise 

 stimulated it will, as Jourdan (4, p. 43) has already observed, 

 go off of itself and elongate In the same manner as those 

 normally thrown out by the animal. My experience in trying 

 to preserve these organs for histology shows this still plainer. 

 Wishing to preserve material for a study of the minute struc- 

 ture of these organs, I carefully removed from freshly opened 

 animals the portion of the respiratory tree to which they were 

 attached and transferred the organs so removed to various 

 preserving liquids. In the process of removal great care was 

 necessary, as the organs. If sliaken or pricked, were liable to 

 go off. But I found that in very few preserving fluids was it 

 possible to preserve the organs in their normal form. For 

 instance, the instant they were placed In a saturated solution 

 of corrosive sublimate every single organ commenced at once 

 to elongate rapidly, and it was some seconds before the killing 

 action of the fluid overcame the tendency to elongate. The 

 same result came about whether the solution was warm or 

 cold, and also in Kleinenberg's picric, in corrosive and acetic 

 mixtures, and in various strengths of chromic. The latter 

 reagent was most useless of all, as it was a long time before 

 the activity of the tubes was overcome. After trying a great 

 many things I was only able to preserve the organs in their 

 normal condition in 1 per cent, osmic acid and in a mixture 

 of corrosive sublimate and osmic acid. Jourdan (4, p. 43) 

 mentions some similar experiences. 



It is obvious that here there can be no question whatever 

 of the elongation being due to pressure of fluid. The 

 Cuvierlan tubes each possess a sort of automatic power of 

 rapidly elongating, the explanation of which must be sought 

 for in the structure of the organs themselves, and which 

 therefore I am not able at present to give. Hence I mistrust 

 Herouard's experiment, for in Holotkuria nigra the organs 

 can be made to elongate whether the cloaca be ligatured or 

 not. Nevertheless It would seem, from the combined evidence 

 of Semper and Hcrouard, that in some forms the Cuvierlan 

 organs are capable of dilating and contracting In response to 



