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\ll. Additional Note on the Contraction of Voluntary Muscle in the Living Body. 

 By William Bowman, Esq., F.R.S., Societ. Philomath. Paris. Corresp., Demon- 

 strator of Anatomy in King's College, London, and Assistant Surgeon to the 

 King's College Hospital. 



Received April 15, — Read April 29, 1841. 



In my paper of June last, published in the Philosophical Transactions*, I showed, 

 by observations on the Rigor Mortis, that contraction, in voluntary muscle, essen- 

 tially consists of an approximation and change of form of the minute particles com- 

 posing its structure ; the phenomena of contraction in living Monoculi and Arguli 

 were also briefly adverted to, but it remained undecided in what manner these 

 minute movements are employed in the higher animals, in the production of motion 

 during life. The almost insurmountable difficulty of submitting the living muscle of 

 the Vertebrata to high powers of the microscope, so much enhances the value of any 

 facts bearing on this obscure point, that I am induced to lay before the Society a 

 short account of some recent examinations of human tetanic muscle, which, with the 

 considerations accompanying them, appear to me to afford conclusive evidence on 

 the subject. 



Two opportunities have lately occurred to me of carefully observing the conditions 

 of the muscular system, in cases of fatal tetanus, and the following has been the result : 



1 . Many muscles appear healthy in all respects. 



2. Parts of certain muscles present a remarkably pale gray aspect, arising, doubt- 

 less, from their blood having been pressed out by the contraction, a state of which the 

 appearance has been aptly compared by my friend Professor Budd, to that of the 

 flesh of fishes. 



3. In other situations, the muscles have lost in a great measure their fine fibrous 

 character, and present a soft mottled surface, which readily tears, or receives an im- 

 pression from the contact of the finger, a condition with which may be associated, 



4. Extensive ecchymoses, often contrasting strangely with the pallor of contiguous 

 portions. 



On microscopic examination, while the other affected muscles appear natural, the 

 primitive fasciculi of those which have lost their texture or are ecchymosed (3. 4.), 

 are by no means so, but present at certain points characteristic marks of a high 

 degree of contraction ; they are swollen into a fusiform shape, and have their 

 transverse striae very much closer together than usual (Plate II. (a)). Elsewhere 

 these primitive fasciculi are, on the contrary, diminished in diameter, and their 



* Part II., 1840. 



