5 The Introduction.^ 



ture^ it being a thin expanded Subjiance^ whieh has 

 Length and Breadth, without much Thicknefs ; fo that it 

 feems only to be made up of Jingle Threads y laid kngthways 

 and acrofs, like a fine Web. We find feme of them pretty 

 thick ^ efpe daily towards their Origin ; but others much thin- 

 tier than the Film of an Egg : The whole Body is ixrap'd up 

 in one of thefe, and every particular Part has a membranous 

 Cover, mchich preferves it from the Injuries it would be ^x- 

 pos^d to from thoje Farts which lie next it, Sotne Farts are 

 involv din double Membranes, as the Brain, and Pith of the 

 Back, i^c, which are very foft and delicate ^ and could ?iot 

 be eafily preferved by afingle one. 



But befides their Office of covering and defending all Farts 

 of the Body, feme of thetn ferve as Bags or Cafes for 

 Food and Excremefjts ; others are form'd into Conduits, for 

 the Blood and arwnal Juices, But fome of thefe being part- 

 ly mufcular, and partly membranous, they may be properly 

 faid to be of a mix'd Nature, as are mojl of the MufeleSy 

 and many other Subjlances throughout the Body, 



The Mufcles are made up of flej})y and tendinous Fibres ; 

 ivhich Kind of Structure is necejfary to their Action, they 

 being the Injiruments of Motion, Almoji all Mifcles are 

 flejhy and foft in the Middle, and for that Reafonare capable 

 6f being contracted and dilated ; for if they were otherwifey 

 it would be impojjible for any Creature to move : Whereas 

 by the Figure they are of, ive find them ready to anfwer 

 every Inclination of the Mind, ivithout Fain or Stijfnefs, 

 The Mufcles are of different Figures, fome flat, as thofe on 

 the Rim of the Belly ; others more round, as thofe of the 

 ' Thighs and Legs ; fo7ne of which, towards their Infer t ions ^ 

 terminate in a firong, nervous, fi7ienxy Subjiance^ called a 

 Tendon. 



A Ligament is more compact and firm than a Tendon ^ 

 but not altogether fo hard as a Cartilage, It is that 

 Subjlance which ties the Joints together ; whereof jofne are 

 rou'-id, as thofe which 'we ohferve faftened to the Head of a 

 Boney and the In fide of its Socket ; ethers are fiat, and co- 

 ver the Joints like p inany Fieces of Leather nail*d on, to 

 keep the two Bones from falling afunder^ and to prefer ve an 

 Uniformity in their Motion, 



A Cartilage, or Griftle, which we obferve more or lefe 

 at the Ends of rnoft Bones, is harder and lefs pliable than 

 the Ligaments : Thefe being of a fmooth Surface, and 

 moderately thick ^ are a Defence to the E?ids of the Bones, 



which 



