No. 380.] REVIEWS OF RECENT LITERATURE. 593 
The work is necessary and will never be abandoned. But while 
some of us have kept exclusively at this sort of work, others have 
begun to study insects from other points of view. What these others 
have done is pretty fairly set out in Dr. Packard’s new book. From 
a knowledge of what has been done come the knowledge of what 
there is to do and the inspiration to do it. If this work done and 
to be done is an especially interesting and especially important kind 
of work, the pioneer text-book of such work is especially valuable 
and helpful. That the kind of entomology treated of in Dr. Packard’s 
text-book is especially important and interesting will not be ques- 
tioned in 1898 nor thereafter. 
The author of such a text-book has a large undertaking on his 
hands, and one to which a great deal of time may be given. To de- 
cide on the quantity of matter to be included and the character of its 
treatment is a nice question, and opinions regarding it will most cer- 
tainly vary. Dr. Packard is an entomologist widely acquainted with 
the work done by other entomologists and zodlogists, and especially 
capable, from his own wide range of study, to judge of the value of this 
work. He is in a position to write as an authoritative critic. We (if 
there are others of my way of thinking) should wish, then, to have him 
present in a text-book of entomology what seem to him, from his 
own investigations and from his knowledge of the observations and 
theories of others, the facts and theories accepted by the consensus 
of authority. We want a well-digested, clearly presented, authoritative 
statement of the present knowledge of insect morphology, physiology, 
and development. This, it seems to me, Dr. Packard has not wholly 
done. The author has wished to be very fair. He presents to us 
the original sources of his knowledge. He displays the contradict- 
ing observations and speculations of investigators; he quotes Ger- 
‘man and French writers in their own words and sometimes in their 
own language; he is strenuous to give credit to whom credit is due. 
This is delusive fairness. It is too much to expect, it is confusing, 
it is impossible for a text-book to give credit for all facts. It is im- 
Possible for Dr. Packard to give all the observations and theories 
pertinent to the structure and physiology of the Malpighian tubules 
or to the origin and development of the imaginal discs. But it is 
wholly possible for him to give us, regarding the Malpighian tubules 
and the imaginal discs, a statement of the present knowledge of 
these organs made by the man best fitted, probably, of all men in 
America to make an authoritative statement of such knowledge. This 
is one conception of what such a text-book from Dr. Packard should 
