494 LIFE HISTORY STUDIES OF ANIMALS. 



But the abyssal and the fluviatile faunas have much in coramon^ as 

 also have the littoral and the pelagic faunas. Kelative density and 

 continuity of x)opulatiou seem to be of vital importance, and it is chiefly 

 these that act upon the life history. 



In zoology, as in history, biography, and many other studies, the 

 most interesting part of the work is only to be enjoyed by those who 

 look into the details. To learn merely from text-books is notoriously 

 dull. The text book has its uses, but, like other digests and abridg- 

 ments, it can never inspire enthusiasm. It is the same with most lec- 

 tures. Suppose that the subject is that well-worn topic, the alternation 

 of generations. The name recalls to many of us some class room of 

 our youth, the crudely colored pictures of unlikely animals which hung 

 on the walls, and the dispirited class, trying to write down from the 

 lecture the irreducible minimum which passes a candidate. The lec- 

 turer defines his terms and quotes his examples; we have Salpa^ and 

 Aurelia, and the fern, and as many more as time allows. How can he 

 expect to interest anybody in a featureless narrative, which gives no 

 fact with its natural circumstances, but mashes the whole into pemmi- 

 can? What student goes away with the thought that it would be good 

 and pleasant to add to the heap of known facts'? The heap seems 

 needlessly big already. And yet every item in that dull mass was 

 once dee^jly interesting, moving all naturalists and many who were not 

 naturalists to wonder and delight. The alternation of generations 

 worked upon men's minds in its day like Swammerdam's discovery of 

 the butterfly within the caterpillar, or Trembley's discovery of the bud- 

 ding Hydra, which, when cut in two made two new animals, or Bonnet's 

 discovery that an Apliis could bring forth living young without having 

 ever met another individual of its own species. All these wonders of 

 nature have now been condensed into glue. But we can at any time 

 rouse in the minds of our students some little of the old interest if we 

 will only tell the tale as it was told for the first time. 



Adalbert Ghamisso, who was in his time court page, soldier, painter, 

 traveler, poet, novelist, and botanist, was the son of a French nobleman. 

 When he was 9 years old he and all the rest of the family were driven 

 out of France by the French Revolution. Ghamisso was educated any- 

 how, and tried many occuijations before he settled down to botany and 

 light literature. In 1815 he embarked with Eschscholtz on the Eussiau 

 voyage round the world, commanded by Kotzebue. The two natura- 

 lists (for Ghamisso is careful to associate Eschscholtz with himself, and 

 even to give him priority) discovered a highly curious fact concerning tlie 

 salpse, gelatinous tunicates which swim at the surface of the sea, some- 

 times in countless numbers. There are two forms in the same species, 

 which differ in anatomical structure, but especially in this, that one is 

 solitary, the other comi)osite, consisting of many animals united into a 

 chain which may be yards long. Ghamisso and Eschscholtz ascer- 

 tained that the solitary form produces the chain form by internal bud- 

 ding, while the chain form is made up of hermaphrodite animals which 



