from which its elongation and contraction is derived. 6 7 
demonstrated in the annexed drawing ; since I cannot 
believe Mr. Bauer has been led into any error upon this 
occasion ; as no error has been detected in his microscopical 
observations for so many years continued, and the accuracy 
of his representations, of what he has seen, no one can 
doubt. 
It is a curious confirmation of the acuteness of his eye, and 
the accuracy of his glasses, that Leuwenhoek, who used a 
single microscope, and says it is the best that can be made, 
since the magnifying glass is the smallest speck that can be 
seen, declares a muscular fibre to be made of globules less 
than the red globules of the blood ; and Dr. Monro of 
Edinburgh, who published his microscopical observations on 
nerves and muscles, in the year 1783, made chiefly in the 
solar microscope, goes so far as to consider muscular fibres 
to be the continuation of nervous fibres, and gives an en- 
graving of the mode in which the one terminates, or is lost 
in the other. Dr. Monro, it is evident, had never seen a 
single fibre either of a nerve or muscle, only fasciculi of them, 
and found them so much alike as to be led to consider them 
the same. Both Leuwenhoek and Monro, from the want 
of a micrometer, were left to guess at relative dimension, 
and in such guesses were often very unsuccessful. 
The globules in the nervous fibre being smaller than in 
the muscular, oversets Monro’s theory of their being the 
same ; but that both authors, with means so very inadequate 
to those employed by Mr. Bauer, should have made such 
approaches to the truth, is highly creditable to them, and 
must prove highly satisfactory to Mr. Bauer, as well as to 
the public. 
