DEFECTS OF THE SENSES. A2I 
its host. Like Dodder, all the species are leafless. One species 
occurs in New Zealand. 
I might go on dealing interminably with other modifications of 
leaves, stems, &c., but I am afraid that I have already wearied you 
beyond all patience. But my object, in which I hope I have 
succeeded, has been to show, not so much the singular modifications 
which organs undergo, as the fact that we seem to have before us a 
completely graded series of modified organs. We hardly ever come 
across any organs which are so singularly formed as to have no others 
like them in other and usually allied plants. And even when we do 
come on any structures at first sight inexplicable, a careful examina- 
tion of its relatives usually helps us in comprehending it. As I said 
in my first lecture, the key to all this has been the doctrine of evolu- 
tion; by its means we are able to open up problems that were 
inexplicable to the older scientific men, and thus to let a flood of 
light in on the science of morphology. Personally, I am so impressed 
with the correctness of the doctrine in this relationship, that when- 
ever I come across any intelligent person who is inclined to pooh-pooh 
the thing, I always feel that the one tonic requisite is a course of 
practical botany or zoology under a competent instructor. But the 
fact is that at the present day, there are few, if any, intelligent 
persons, who know anything of the subject, who do not assent to its 
leading principles. 
(To be continued ). 
IS THERE A CORRELATION BETWEEN DEFECTS OF THE 
SENSES ? 
(The following important paper by Professor Alexander Graham 
Bell, is taken from “Science,” of 13th February last. The whole 
subject of the relation of the community at large to those who have 
the misfortune to be blind or deaf and dumb is one demanding most 
careful attention. The tabulated statistics in this paper will repay 
close examination.“—ED.) 
People sometimes assume that a defect of any important sense is 
balanced to the individual by the increased perception of the re- 
maining senses. For instance: it is often thought that deaf persons 
have better eye-sight than those who hear, and that blind persons 
have better hearing than those who see. The returns of. the tenth 
census of the United States (1880) concerning the defective classes 
show clearly the fallacy of such a belief. They indicate that the deaf 
are much more liable to blindness than the hearing, and the blind 
more liable to deafness than the seeing. 
About one person in every thousand of the population is blind, 
and one in every fifteen hundred deaf and dumb. Now, if these 
proportions held good for the defective classes themselves, we should 
expect to find one in a thousand of the deaf-mute population blind, 
* In this connection see a paper by Francis Galton in “‘ Nature” of January 22nd, 
Dp. 269, on ‘‘ Hereditary Deafness.” 
