GOLGI APPARATUS IN STRIATED MUSCLE. Ill 



conclusion which occurs to me is that in insects the Golgi appa- 

 ratus seems characteristically to occur in the form of scattered 

 Golgi bodies, rather than a network comparable to the condition 

 usually found in mammals. On the other hand, the silver 

 methods have been tried so often, and by so many people, that 

 if there is a Golgi apparatus in the insect muscle fiber other 

 than the network mentioned, it ought by every possibility to 

 have come to light. It may therefore be tentatively concluded 

 that the so-called muscle "network of Cajal-Fusari " represents 

 the Golgi apparatus (and all of it) in striated (skeletal and heart) 

 muscle fibers of both vertebrates and invertebrates. 



It is to be noted that all the results thus far obtained have 

 depended upon the use of silver nitrate, usually following the 

 Golgi fixation in osmium-bichromate. It would be interesting 

 to know whether other methods, which have proved specific 

 for the Golgi apparatus, would reveal the same network, or 

 material arranged in some new way. Recently while studying 

 some preparations of Cowper's gland from the cat, I found 3ome 

 fragments of striated muscle which, inadvertently included with 

 the glandular tissue, had been impregnated by osmic acid ac- 

 cording to Nassonov's ('24) modification of Kolatchef's method. 

 Following this treatment a great variety of pictures results. 

 The cross striations may be very clearly demonstrated, after 

 the well-known reaction of osmic acid on striated muscle. 

 Various other ways of impregnating the muscle substance also 

 occur, of which an interesting one is the specific blackening of the 

 sarcoplasrn while the muscle columns or fibrils are relatively 

 unstained. A cross-section of a portion of a muscle fiber thus 

 impregnated is shown in Fig. i . 



In one case a very unusual impregnation was found, in which 

 both muscle fibrils proper and sarcoplasrn failed to blacken in 

 the least, while fragments of a network lying between the muscle 

 columns were rather clearly impregnated. A small section of 

 such a muscle fiber is shown in Fig. 2. The muscle columns are 

 indistinctly differentiated as longitudinal bands. The network 

 consists of longitudinal and transverse threads along which 

 granular thickenings occur at rather regular intervals. Except 

 for the fact that the longitudinal fibers are unusually numerous 



