542 Cnroliuo .MeGill. 



7. Ihcve appears to be no change in the volume of smooth muscle 

 nuclei (hiring contraction. 



8. Fatigne was shown to cause no apparent change in the structure 

 of the nuclei. 



9. Xuclei in nuiscJe contracted bj pilocarpine, adrenalin, atropine, 

 etc., have the same structure as nuclei contracted by electrical or 

 mechanical stimuli. 



10. During contraction more change- take place in smooth muscle 

 than can be attributed to morphological causes, such as thickening 

 of the myofibrilke, etc. At the contraction nodes the staining reac- 

 tions would indicate that there is a marked chemical reaction taking 

 place also. 



11. The development of contraction was studied in chick and pig 

 embryos. The muscle cells become contractile soon after the myo- 

 fibrilhie appear. Thus in the chick, where the myofibrilla? arise on 

 the fifth day, distinct contraction was obsarved on the seventh day. 

 This, together with the fact already mentior.ed that the myofibrillar 

 become shorter and thicker during contraction, wculd seem to indi- 

 cate that the mvofibrillie ai'e the contractile elements. Contrnction 

 waves do not aj^pcar until comiiaratively late in development. 



LITEKATFIJE LIST. 



(raiK-rs not accessihle in the original niavkod *.) 



1. Apathy, ISOO. Nncli wcldier Itiditung liin si;ll die Nci-vcnlehre rcfov- 



miert werdenV Biol. CtMitrallil., I'd. !>. 



2. Arnold. ISTl. Stride ers Ilandbndi der Geweiu'lehic. 



3. BARFrRTH. tSOl. Uebev Zellbriidven glatter Mus;:( U'ascrn. Avdi. f. 



mikr. Anat., Bd. 3S. 



4. Be]vda, 1002. Ueber den feineren Ban dvv flatten Mnskeltasern des 



Mensdieu. Anat. Anz.. Bd. 21. 



5. BoHEMANN. 1895. Intercellnlarliriicken nnd Sal'rriinme der ,!j;latten Mns- 



kulatur. Anat. Anz.. Bd. lo. 

 G. Bbuyne de. 1895. Beriditiiiini.^ zu II. Boheuianns V(n-liir.ii.iier >[it- 

 teilung iil)er Intercellnlarbi-iicken nnd Saltriinnie der .flatten >[ns- 

 knlatnr. Anat. Anz.. Bd. In. 



7. Drasch, 1895. Der Ban der (liftdriisen des ,ij;etieckten Salamanders. 



Arch. f. Anat. u. Physiol.. Anat. Abth.. 1895. 



8. FLEMiiiXG, 1878. Ueber Fornien nnd Bedentnni,' der ori,'anis> het' Mns- 



kelzellen. Zeit. f. Wiss. Zool., I!d. :!<i. 



