242 
NWATOURE 
[Juty 13, 1899 
sixteen! genera of the former into twenty-one. If 
specific names were taken into consideration, further 
discrepancies would be noticeable. Moreover, in many 
of the other families of birds the two authors do not 
agree in regard to several of the generic names. For 
example, in the case of the ruff and reeve Mr. 
Saunders retains the Cuvierian (Jachezes, while Dr. 
Sharpe employs the earlier Pavoncel/a. 
Such differences and idiosyncrasies are irritating 
enough to the working naturalist who knows what he 
is about, but to the amateur and the beginner they must 
be absolutely maddening. Although personally we are 
inclined to side with Mr. Saunders in regard to the 
limits of genera, and with Dr. Sharpe in regard to the 
adoption of the earliest names for the same, we consider 
both matters of no importance at all in comparison with 
uniformity of usage. And it is, we think, high time 
ornithologists settled upon some uniform working basis. 
Otherwise, we are of opinion the sooner scientific names 
are given up the better; they were intended for our 
tools, and we are rapidly making them our masters. 
In the last few paragraphs we have departed rather 
widely from our text; and, to revert to the same, we 
may conclude by expressing the hope that the second 
edition of the “ Boy’s Yarrell,” as the work before us has 
been not inappropriately termed, may meet with as 
favourable a reception from the public as has been 
accorded to its predecessor. IR Ibs 
AS REGARDS REGENERATION. 
Thatsachen und Auslegungen in Bezug auf Regenera- 
zion. Von August Weismann. Pp. 31. (Jena: 
Gustav Fischer, 1899.) 
ROF. AUGUST WEISMANN’S essay on regener- 
ation, which appeared simultaneously in Watural 
Science and in the Anatomischer Anzeiger, has now been 
published in pamphlet form, and well deserves the 
careful consideration of biologists. Its contents may be 
divided into two parts, the first of which is independent 
of the second. In the first part, Prof. Weismann ex- 
pounds his previously expressed conclusion that re- 
generation is an adaptive phenomenon—“that the 
regenerative power of a part is to be considered, not as 
a direct and necessary expression of the nature of the 
organism, but rather as a capability which, though it 
may be absent, is found wherever it is necessary in the 
interests of species-preservation.” In other words, the 
power of regenerating lost parts, though depending 
primarily (like all other vital qualities) on the properties 
of organised protoplasm, has been defined and perfected 
in the course of natural selection in those organisms 
which are in the ordinary course of their life frequently 
liable to serious mutilation. This is not a new idea, for, 
as Weismann notices, Réaumur made, in the first half of 
the eighteenth century, the induction that the power of 
regeneration was especially characteristic of animals 
whose brittle body was frequently liable to risk of 
breakage, and also of those, like earthworms, which are 
liable to be partially devoured. The Italian naturalist 
Lessona gave more precise expression to the same in- 
1 Lusciniola, for Radde’s bush-warbler, was not known to be British 
when Dr. Sharpe wrote. 
NO. 1550, VOL. 60] 
duction in what is sometimes called ‘“‘ Lessona’s law,” 
while Darwin regarded the regenerative capacity as in- 
terpretable on his theory of the selective origin of 
adaptations. 
But since the days of Lessona and Darwin the wide 
occurrence of regenerative capacity throughout the animal 
series, till it fades away to almost nothing in mammals, has 
been more adequately appreciated, and besides obsery- 
ations not a few experiments have been made, so that 
the literature of the subject is already enormous 
Weismann, more perhaps than any other, has the credit 
of having recognised the importance of the problem pre- 
sented, and of having tried to face the facts with a 
theory. 
The first part of the pamphlet is an argument in 
favour of the interpretation of the regenerative power 
as an adaptive phenomenon. (1) It has been objected 
that regeneration sometimes occurs where the loss could 
only be called a casualty, and not such as would occur 
in the ordinary course of nature, e.g. a bird’s_ re- 
generation of a broken beak, or a newt’s regeneration of 
aneye. But as one inquires further into the matter it 
becomes probable that these injuries are much more 
frequent than was imagined, and that they cannot be 
called casualties. (2) It has been objected that internal 
organs not naturally exposed to mutilation or periodical 
wearing out are sometimes regenerated. But there 
seem to be few cases where this has been really sub- 
stantiated, though some observations—by Vitzou, for 
instance, on monkeys—lead us to doubt whether 
Weismann is quite warranted in saying that regener- 
ation of brain-cells'in mammals never occurs. (3) T. H. 
Morgan’s experiments on hermit-crabs showed that all 
the appendages were capable of regeneration, both those 
most liable to injury and those naturally well-protected, 
and led him to the conclusion that there is no relation 
between the frequency of loss and the regenerative 
capacity. With this case Weismann deals at consider- 
able length and with his wonted ingenuity, calling to 
his aid especially the idea that the variation of the re- 
generation-“anlage” may lag behind the phyletic trans- 
formation of the part in question. But is it not enough 
to say that the fallacy underlying Morgan’s objection is _ 
that of treating an organism as a finished product, and 
of assuming that an adaptation must be perfect? (4) It 
has been objected that regeneration does not occur in 
many cases where it would be very useful, thus its 
occurrence among reptiles, as regards the tail, is strangely 
sporadic, one might be tempted to say capricious. But 
is not this an argumentum ad tgnorantiam, is it not 
likely that as we know more about the actual conditions 
of life in the apparently puzzling cases, the difficulties 
will disappear? Moreover, must it not be admitted that 
the absence of regeneration may be explained by the 
presence of another life-saving adaptation on totally 
different lines, and that, after all, adaptations are but com- 
promises, and by no means perfect? Thus it is hardly 
an argument against the generally adaptive character of 
regeneration in earthworms to cite a case where the 
mutilated creature grows a second tail instead of a new 
head. One might as well say that the quickness of 
cerebral activity was not an effective adaptation because 
some people sometimes lose their heads. 
