ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
297 
Wolff’s main point is that all vital phenomena are adaptive; useful 
adaptation is the very essence of an organism ; to try to explain adaptation 
is to try to explain life. 
Herr Wolff made the following experiment. He removed the lens 
from the larva and adult of Triton tseniatus. In a few months it was 
perfectly regenerated by the iris. The inner epithelial layer of the iris 
lost its pigment, proliferated at the margin of the pupil, and formed a 
lens-sac, and eventually a perfect normal lens. 
Inheritance of Acquired Characters.* — Prof. A. S. Packard dis- 
cusses this subject under several heads. He commences with the physical 
basis of heredity, and appears to incline to the theory of Hertwig. He 
next treats of the heredity of characters acquired during the lifetime of 
the individual, in which he expresses his admiration for the observa- 
tions of Herbert Spencer on this subject. He concludes that “ we feel 
justified from the facts now known in holding the view that characters 
acquired in the lifetime of an individual, as the result of functional 
activity in certain regions of the body, or in certain organs, may under 
favourable conditions be more or less completely transmitted ; or at 
least the tendency to such transmission, if latent in one generation, 
may appear in a succeeding one; and in the earlier geological ages 
this principle may have been much more active than at present. The 
hypothesis seems to be a good working one to account for phenomena 
which cannot be otherwise explained, and should not in consequence of 
adverse, though often very able and candid, criticism be set aside.” 
Inheritance at corresponding periods of life is next treated, and what 
the author thinks to be signal examples of the inheritance of characters 
at corresponding periods of life are cited. The fourth section of the 
essay deals with homochronous heredity in insects with a hypermeta- 
morphosis. The examples cited are thought by the author to be 
evidently the result of adaptation in response to a series of stimuli 
whose nature is in part appreciable, but in part unknown. In treating 
of the inheritance of acquired characters by Lepidoptera Prof. Packard 
is dealing with a subject which he has made more particularly his 
own, and he concludes with a plea in favour of the adequacy of 
Neolamarckism. 
Subterranean Fauna of North Anierica.f — Prof. A. S. Packard 
discusses the origin of the subterranean fauna of North America, in the 
course of which he complains of some of the more eminent writers on 
this subject, such as Professors Weismann and Ray Lankester, who have 
not themselves had practical experience in collecting and studying cave 
animals and their surroundings, and who have not carefully read the 
recent literature on the subject ; they seem to be overmastered by specu- 
lative views, and prefer to make an extremely vague, unscientific, and a 
priori speculation rather than adopt an opinion based on the inductive 
method. Mr. Herbert Spencer, however, has with rare good sense and 
penetration recognised the probability of the active agency of the prin- 
ciple of transmission of acquired characters in the origin of cave life. 
The author compares with subterranean fauna the experience gained by 
* Proc. Amer. Acad., xxix. (1894) pp. 381-70. 
t Amer. Nat., xxviii. (1894) pp. 727-52 (1 pi.). 
