136 Book Reviews

of some new diseases, and a reminder of diseases already
described in the Amish population. Much of the first
half of the book is concerned with nosology, and an
excellent chapter is that by P. E. Becker on the spastic
paraplegias and spinocerebellar ataxias. He has brought
interest and order to a difficult branch of neurology.
Some of the other chapters on nosology are tedious and
wordy. However there are some unusual topics
covered in this book. For example, there are useful
descriptions of some viral infections of the central ner-
vous system, some of which give rise to malformations
such as neural tube defects, cerebellar degeneration, and
aqueduct stenosis; while others lead to the degenera-
tive-occasionally familial-disorders of scrapie, kuru,
and Creutzfeldt-Jacob disease. In another chapter,
W. E. Nance discusses the aetiology of anencephaly
spina bifida, mentioning the facts that only a small pro-
portion of like-sexed twins are concordant for neural tube
malformation, that maternal half-sibs have a recurrence
risk as high as that of full sibs, and that the increased
incidence in second and third-degree relatives is largely
confined to matrilineal relatives. Dr Nance suggests
that the explanation for these observations is that in-
heritance is through cytoplasmic factors.

Chapters which are more clinically oriented include
good ones on Tay-Sach's disease, Refsum's disease with
an account of dietary treatment in two patients, and
descriptions of some of the childhood leucodystrophies.
Of particular interest in the case reports in the later part
of the volume are those autosomal recessive conditions
associated with mental retardation, where diagnosis and
subsequent genetic counselling are so important. Such
disorders include an oculocerebrofacial syndrome where,
in addition to retardation there is microcomea, optic
atrophy, and small mandible; an example of the Dyggve-
Melchoir-Clausen syndrome with mental deficiency;
and familial megalencephaly. In all this is a helpful and
interesting volume in the Birth Defects series.

SARAH BUNDEY

Genes, Dreams and Realities. By Sir Macfarlane
Bumet. (Pp. 232; illustrations. C2 75.) Aylesbury:
Medical and Technical Publishing Co. Ltd. 1971.

All that Sir Macfarlane Bumet writes must be treated
with respect and in this book he discusses several of the
most important biological issues of the day: the human
applications of the new biology; the implications of the
treatment of genetic disease; the immunological basis of
carcinogenesis and of ageing; and the possibilities of
population control. On most of these issues his con-
clusions are pessimistic and many readers will regard him
as being unduly so; but will find it a valuable exercise to
think out just where they feel he may be mistaken. On
a more technical level the book is noteworthy in empha-

sizing the author's view of the importance of somatic
mutation, as opposed to mutation in the germ cells, as a
cause of disease.
He thinks that basic work on molecular biology is now

largely completed except for the elucidation of the
structure of ribosomes in relation to their function of
translation and a complete specification of an RNA
bacteriophage. He regards the chance of discovery of
practical methods of direct gene replacement in man as
infinitely small. He does however think that there is a
reasonable chance of culturing and transforming some of
the patient's own cells and returning them to the body so
that they can compensate for genetically determined
deficiencies.
He notes the difficulty that many doctors still have in

accepting that a disease has a genetic cause and reminds
us that this was once equally true for the concept that
some diseases were due to invasion by microorganisms.
He is doubtful of the ethics of treating children with
disorders such as PKU and notes 'it will probably be
many years before the logical solution can be accepted
that infants with gross genetic defects of metabolism
should be treated as those with no brains (anencephalic
monsters) ... and not allowed to survive'. Most medi-
cal practitioners perhaps would agree only if the detec-
tion and destruction of those affected could be readily
achieved early in pregnancy, always provided of course
that this is what the parents wanted. He makes a good
case for the origin of cancers from somatic mutation and
the reviewer was interested to learn that tumours in pure
line strains of mice induced by carcinogenic chemicals
are each antigenetically different. Bumet is sceptical of
the view that viruses play much part in the aetiology of
cancer on the grounds that he can see no selective ad-
vantage to a virus in inducing cancer in the host. He
thinks that immune mechanisms control much potential
cancer and offer the best hope for a cure. He believes
however that 'little further advance can be expected
from laboratory science in the handling of the 'intrinsic'
type of disability and disease'.
On population problems he is equally pessimistic. He

believes it necessary to get back to a global population of
between one and two million until a greater proportion of
solar energy can be harnessed by collectors in geo-
stationary orbit which can beam energy onto the earth's
surface. The control of population he regards as quite
the most important priority. 'Family planning with its
slogan of the children you want when you want them is
absolutely inadequate; it is population control or
chaos.' However he does not believe that any demo-
cratic country will ever initiate effective policies of
population control so that 'current civilization will de-
stroy itself and that a second civilization rebuilt in cen-
turies or more millennia from pockets of survivors will
probably again end in another catastrophe'.

C. 0. CARTER

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