244 



expressed in digits of the ternary scale of notation, every digit be- 

 ing either — 1, 0, or + 1. In this system, unity being, in multi- 

 plication, only an index, the rules for multiplication and division 

 must consist entirely in directions for the management of the signs 

 of unity ; and it is on this principle that Mr. Fowler's machine is 

 made to act. A short account is given of the principal parts of the 

 machine, and of the mode in which they bring out the final results. 

 It is necessary, however, in applying it to use, to have recourse to 

 tables, both for converting the factors and reconverting the result ; 

 operations which introduce both labour and risk of error. 



1 1 . On the Minute Structure and Movements of Voluntary Mus- 

 cles, in a letter addressed to R. B. Todd, M.D., F.R.S., &c. By 

 William Bowman, Esq., Demonstrator of Anatomy in King's Col- 

 lege, London, and Assistant Surgeon to King's College Hospital. 

 Communicated by Dr. Todd. 



The objects of the author, in this paper, are the following. — 1st. 

 To confirm, under some modifications, the view taken of the primi- 

 tive fasciculi of voluntary muscles being composed of a solid bundle 

 of fibrillse. 2dly. To describe new parts entering into their com- 

 position : and 3dly. To detail new observations on the mechanism 

 of voluntary motion. 



He first shows that the primitive fasciculi are not cylindrical, but 

 polygonal threads ; their sides being more or less flattened where 

 they are in contact with one another ; he next records, in a tabular 

 form, the results of his examination of their size in the difi"erent di- 

 visions of the animal kingdom. It appears that the largest are met 

 with in fish ; they are smaller in reptiles, and their size continues 

 to diminish in insects, in mammalia, and lastly, in birds, where 

 they are the smallest of all. In aU these instances, however, an 

 extensive range of size is observable, not only in different species, 

 but in the same animal, and even in the same muscle. He then 

 shows that all the fibrillse into which a primitive fasciculus may be 

 split, are marked by alternate dark and light points, and that fibrillse 

 of this description exist throughout the whole thickness of the fasci- 

 culus ; that the apposition of the segments of contiguous fibrillse, so 

 marked, must form transverse striae, and that such transverse striae 

 do in fact exist throughout the whole interior of the fasciculus. He 

 next inquires into the form of the segments composing the fibrillae, 

 and shows that their longitudinal adhesion constitutes fihrillce, and 

 their lateral adhesion discs, or plates, transverse to the length of the 

 fasciculus ; each disc being, therefore, composed of a single segment 

 from every one of the fibrillse. He shows that these discs always 

 exist quite as unequivocally as the fibrillae, and gives several exam- 

 ples and figures of a natural cleavage of the fasciculus into such discs. 

 It follows that the transverse striae are the edges, or focal sections of 

 these discs. Several varieties in the striae are then detailed, and the 

 fact noticed that in all animals there is frequently more or less di- 

 versity in the number of striae in a given space, not only on conti- 

 guous fasciculi, but also on the same fasciculus at different parts. 



