Notes on Recent Literature. 
340 
which to carry on its life, of how these movements can be analysed, 
by suitable experiments in the laboratory, into a series of “tropisms,” 
impressed rhythms, and “tones,” of exactly the same nature as 
those with which the plant-physiologist is familiar in the reactions 
to light and gravity of the higher plants, the whole combining to 
adapt the “ plant-animal ” perfectly to its sharply defined place in 
nature, constitutes a study of quite exceptional charm. 
Not less attractive is the record of how Professor Keeble solved 
the problem of what the alga which forms the green cells of 
Convoluta roscoffensis really is, and how it gets into the animal; of 
the anxiety of the animal to receive its guest, of its wretched 
condition when “ infection ” is prevented, and of how when the alga 
is safely ingested, both host and lodger live a life of enervating 
luxury, the alga on the nitrogenous waste products of the worm, the 
worm on the carbohydrates of the alga ; of how, probably owing to 
the gradual waste of nitrogen, an end comes to this delightful 
arrangement, the animal is forced to digest its benefactor, which 
has lost its cell-nucleus and is unable to resist the process. Both 
organisms have found a short cut to a livelihood, the animal gives 
up its power of eating solid food and finally dies as the result, but 
since it is still able to reproduce its species, it has, biologically, the 
best of the bargain. The plant, driven by the nitrogen famine of 
the open sea, finds abundance of food and a perfectly protected 
home, for a time (!) in the body of the animal. Those individuals 
which choose this easy path lose their power of reproducing their 
kind—the species is maintained by the self-dependent autophytic 
individuals which remain outside. 
Heredity. 
Mr. Doncaster’s little book 1 in the same series is a very able 
and clearly written summary of the present position of Our 
knowledge of heredity, characterised by a judicial readiness to give 
full weight to rival schools, which is unfortunately rather rare with 
writers on this subject. It may be cordially recommended as an 
introduction to the subject, and to those who lack time or 
inclination for further study A.G.T. 
The Cambridge Manuals of Science and Literature, edited by 
P. Giles and A. C. Seward, is the general title of a new series to 
which both these books belong, issued by the Cambridge Univer¬ 
sity Press. They are intended to be “ short books in which recent 
discoveries or modern tendencies are treated with semi-popular 
and broad style not in any sense general text-books but 
essays on particular branches of knowledge.” The series, which 
has certainly made a good beginning, promises to contain many 
interesting and attractive volumes, and the very low price of each 
(one shilling) will place them within easy reach of a wide circle of 
readers. The general title is, perhaps, not very happy ; a “ manual ” 
rather conveys the idea of the detailed hand-book, the “ stodgy ” 
if necessary occupant of the laboratory or study table. 
* “Heredity in the Light of Recent Reseach,” by L. Doncaster. 
Pp. x and 140. Cambridge, at the University Press, 1910. 
Price One Shilling. 
