UTAH ACADEMY OF SCIENCES 65 
tion that the child must have had some practice with his 
right hand at the ordinary writing.’ Otherwise there 
will be no mirror-writing by the left hand, ‘‘for those who 
have been allowed to use their left hand freely from the 
first, find rightward writing as easy as do the right- 
handed.” 
These explanations of the physiology of mirror-writ- 
ing are the most plausible extant, and merit acceptance 
but for the fact that a very important type of mirror-writ- 
ing which Fuller failed to investigate, is still an enigma. 
The writer found, after an intensive study of ten typical 
cases of mirror-writing which had appeared in the normal 
school population, that the very first handwriting 
attempts of these children were left-hand reversals. Now 
according to Fuller’s own words: “The child must have 
had some practice with his right hand at ordinary writ- 
ing before ‘mirror-writing’ can occur.” 
Furthermore, according to this theory, the left- 
handed child who writes conventionally with his left- 
hand, and is made to use his right hand will spontaneously 
write mirror-wise with the right hand. The facts, how- 
ever, do not support this hypothesis. 
Again, the implication from these conditions is 
unmistakable that mirror-writing is positively correlated 
with dissociation or insanity. Here again a discrepancy 
arises, since it is a matter of record that while many mir- 
ror-writers are retarded, some are also known to be pre- 
cocious. 
Fuller, however, by his physiological analysis of mir- 
ror-writing has incidently thrown some light upon another 
phase of the problem,—the causal relationship between 
speech aberrations and the changing of handedness. 
A just criticism of Fuller’s method would seem to be 
that he induced reversed, left-hand writing in subjects 
who are not normally “mirror-writers,”’ rather than study- 
ing the characteristics and the spontaneous behavior of 
those who execute mirror-writing normally. The method 
might be likened to a study of insanity made by inducing 
a temporary insanity in otherwise sane subjects. 
The writer’s own results, even with their admitted 
limitations, call for another explanation. In such an 
attempt, it would be futile to neglect or to ignore the sal- 
