OBSERVATIONS ON THE HISTOLOGY OF STRIPED MUSCLE. 71 



I shall next give a resume of the results of some recent 

 observers who are in favour of the existence of a network. 



Van Gehuchten^ has described a network in striped muscle 

 similar in most respects to that described by Melland, myself, 

 and others, but differing in some details. 



Carnoy2 also adopts the network view, and remarks that 

 " La cellule musculaire est une cellule ordinaire dont le reti- 

 culum s'est regularise, et I'enchyleme charge de myosine." 



HaswelP has recently published an important paper on this 

 subject. His observations were made on the gizzard of 

 various species of Syllis, where he claims to have found very 

 primitive forms of striped muscle. He divides striped muscle 

 into simple and compound types, the simple type showing 

 only transverse striation, not due to network ; the com- 

 pound both transverse and longitudinal. These two types 

 correspond to what I have termed true and false striation ; 

 the characteristics of the compound or true striped muscle 

 being as follows : 



1. Each fibre consists of a bundle of fibrils. 



3. Each fibre is composed of two alternating series of 

 anisotropous and isotropous segments^ the former of which 

 are more easily stained than the latter. 



3. Kunning across the fibre in the middle of each iso- 

 tropous segment is the transverse network, or Krause's mem- 

 brane. 



4. Between the fibrils run the strands of the longitudinal 

 network. 



5. Each fibre is formed from a single cell, the nucleus of 

 which divides and forms " a multinucleated protoplasmic 

 body, by modification of whose protoplasm the muscle sub- 

 stance and networks are formed." 



He states that in these animals the elements of the fibre 

 are on a larger scale than in Vertebrates and Arthropods, and 



* " Etude sur la structure intime de la cellule musculaire Striee." Extrait 

 de la Revue 'La Cellule,' t. ii, 2 fascicul. Louvain, Gand et Liege, 188G. 

 ^ 'La Biologic cellulaire,' 1884. 

 3 ' Quart. Journ. Micr. Sci.,' 1889. 



