那么,這又怎樣呢?鯨須,背峰,脊鰭和牙齒;這些特征,不管究竟具有多少其它更主要的特點和結(jié)構(gòu)的特質(zhì),都是各種鯨類所具有的。一無差別的東西。因此,抹香鯨和座頭鯨雖都各有背峰;但是,它們的類似之處也僅此而已。再說,這種座頭鯨和格陵蘭鯨也都各有鯨須;然而,它們之間的類似之處,又是只此而已。至于以上所提到的其它部分也是如此。在各種各樣的鯨類中,它們就有這么不規(guī)則的混同;或者有時其中又有一種是與眾不同的,形成非常不規(guī)則的獨樹一幟。好象是完全不顧一切由這樣一種根據(jù)而形成的一般分類法似的。這種情形是每個研究鯨的博物學家都要大碰其壁的。
But it may possibly be conceived that, in the internal parts of the whale, in his anatomy--there, at least, we shall be able to hit the right classification. Nay; what thing, for example, isthere in the Greenland whale's anatomy more striking than his baleen? Yet we have seen thatby his baleen it is impossible correctly to classify the Greenland whale. And if you descendinto the bowels of the various leviathans, why there you will not find distinctions a fiftieth partas available to the systematizer as those external ones already enumerated. What thenremains? nothing but to take hold of the whales bodily, in their entire liberal volume, andboldly sort them that way. And this is the Bibliographical system here adopted; and it is theonly one that can possibly succeed, for it alone is practicable. To proceed.
不過,也許有人會認為,從鯨的內(nèi)部,從鯨的解剖中,我們至少總能夠摸出正確的類別來。不,比如說,在格陵蘭鯨的解剖中,除了鯨須,還有什么更為顯著的東西嗎?而且,我們已經(jīng)知道,光靠鯨須是不能夠正確地對格陵蘭鯨加以分類的。如果你跑到各種大海獸的肚皮里去,那么,你在那里頭所找到的特征,還是不及那些已經(jīng)列舉出來的外部特征而能自成一系的東西的五十分之一。那又該怎么辦呢?除了抓住鯨的身體,著眼于它們整個龐大的體積,大膽地按照這方法來分類以外,是別無它法可想的。這就是我這里所采用的書目提要的方法;也是可能獲致成效的唯一方法,只有它才是切實可行的。再說下去吧。