196 Journal of Comparative Neurology. 



muscle, we trust that our confirmation of their results with 

 methods differing somewhat from the ones they used, may- 

 prove of some value. 



Mtiscle- Spindles. In 1862, Kolliker described in the cu- 

 taneus pectoris of the frog, peculiar bundles of small muscle 

 fibers, to which, at an expanded portion of the bundle, a rel- 

 atively large medullated nerve fiber was attached. They were 

 designated "muscle-buds" (Muskelknospen), and were re- 

 garded as showing a longitudinal division of muscle fibers and a 

 consequent division of the muscle nerve. 



In the following two years, in three communications, 

 Kiihne mentions similar structures in the muscles of adult rats, 

 house mice, rabbits, lizards and snakes (Coluber natrix) and 

 also in the frog. These structures were described by him as 

 "muscle-spindles" (Muskelspindeln) and, while not assigning 

 to them any definite function, he suggests the possibility of 

 their being other than growth centers. His own words read as 

 follows : "Sind dieselben Apparate miteiner noch unbekannten 

 physiologischen, fiir den Zuckungsvorgang des Gesammtmus- 

 kels wichtigen Function, oder stellen sie nur ein Stadium noch 

 nicht vollendeter Entwickelung einer Muskelfaser dar ? Fiir 

 das Letztere spricht der Umstand, dass der Spindel zuweilen 

 bis hart an den Nerveneintritt hin Querstreifen zeigt, wahrend 

 fiir das Erstere die unverkennbare Aehnlichkeit des nicht gestreif- 

 ten Abschnittes mit den Balken des Schwammgewebes vieler 

 pseudoelektrischen Organe sprechen wiirde. " 



Since the discovery of these structures by Kolliker and 

 Kiihne, they have been repeatedly found and variously inter- 

 preted. We shall not attempt, however, to do more than give a 

 brief summary of the opinions current in the literature con- 

 cerning the muscle-spindles and similar structures. And this may 

 perhaps best be done by classifying them as follows : 



I. They have been regarded as grozvth-centers, following 

 Kolliker in this respect, by Bremer, Felix, v. Franque, Trin- 

 chese, Tanhoffer and Volkmann, also by Schafer and Schiffer- 

 decker. The majority of these investigators have recognized 



