l888.] NEW-YORK MICROSCOPICAL SOCIETY. 9 



could not attain the desired degree of excellence in the prepa- 

 ration of the radulpe, which would enable me to make a com- 

 plete study of their various features. This led to a long series 

 of experiments, performed with all the principal reagents used 

 in microscopical investigation. An enumeration of these ex- 

 periments would add but little to our knowledge, beyond the 

 fact that most reagents are useless for this work, and many are 

 of but little value. 



When manipulating with such small objects as the lingual 

 ribbons of our Rtssotdce, small species of Flanorbis, Goniobasis, 

 Pupa, Vertigo, etc., simplicity is of the greatest moment, for in 

 transferring the radula from one dish to another, and passing it 

 through successive reagents, it is very likely to be lost, or so 

 mutilated in handling as to be worthless. Therefore, a compli- 

 cated or laborious method is to be avoided if possible. 



The transparency of the objects is also another obstacle to be 

 overcome, and while mounting media can be selected of a diffe- 

 rent refractive index, yet the loss of absolute and reliable diffe- 

 rentiation, from the reflection of light from the polished denti- 

 cles, the interference of perspective in media of low refractive 

 indices, and the diffraction lines produced by the minute 

 denticles, render it extremely desirable to stain the specimens, 

 and to mount them in a highly refractive medium, or one that 

 nearly agrees with the refraction of the objects themselves. 



Method of Preparation. — The shells having first been 

 boiled or placed in alcohol to kill the organisms, the animals 

 are extracted from their shells by drawing them out with a 

 mounted needle or hook, and in the larger species the head is 

 cut off, and the remainder of the animal rejected. In the 

 minute species, the shell may be removed by hydrochloric acid. 

 Either process may be employed, to equal advantage, upon 

 shells which contain the dried remains of the animals. 



The specimens are then placed in a small porcelain crucible 

 containing water, in a sand bath over a Bunsen burner. A little 

 boiling will soon render them in a condition for the rapid action 

 of a small piece of caustic potash, which is next placed in the 

 crucible, and the whole allowed to boil until the tissues have 

 become disintegrated and partially combined with the potash. 

 The action of the potash should not be continued after it has 

 completed its work upon the tissues, as continued boiling will 



