480 E. V. Cowdry, 



all the same tiling. Both used Altmaiin's and Benda's method and 

 the iron hematoxylin method of Heidenhain as a means of identifica- 

 tion. Nageotte (1909) records the occurrence of mitochondria in 

 several different types of nerve cells. He believes that they are 

 identical with the neurosomes of Held and the bioblasts of Altmann. 

 Perroncito (1911, p. 341), however, concludes that the mitochondrial 

 formations cannot be regarded as corresponding exactly to the bio- 

 blasts of Altmann or the Filarmasse of Flemming. Duesberg (1910 a, 

 p. 612) remarks that no elements (chondriosomes) persist in the adult 

 nerve liber which may be stained by Benda's method, and Hoven 

 (1910, p. 472) states that the chondriocontes disappear rapidly in 

 development, only a few persisting capable of being stained in adult 

 spinal ganglion cells of the fowl. He concludes, further (p. 479), that 

 these persistent chondriocontes correspond to the internal reticular 

 apparatus of Golgi, the Bimiennetz of Kopsch, etc. Meves also (1910 a, 

 p. 655) arrives at the conclusion that no chondriosomes remain, as 

 such, in adult spinal ganglion cells. 



In this section it will be shown that mitochondria do occur in 

 adult spinal ganglion cells of the pigeon, and the evidence will be 

 deduced chiefly from the application to them of a large number of 

 different forms of recognized mitochondrial technique. While none of 

 these methods, taken alone, is specific for mitochondria, still, as a 

 whole, they furnish conclusive proof of the mitochondrial nature of 

 this series of cell granulations. 



1. Observation in the living unstained condition. — Mitochondria 

 may be seen in the living, unstained, spinal ganglion of the pigeon if 

 the cells are teased out in 0,75 °/o sodium chloride solution, and are 

 examined with the best Zeiss apochromatic lenses. They appear as 

 minute, highly retractile bodies, of uniform size and shape, distributed 

 throughout the cytoplasm. They are sometimes arranged in rows 

 which seem to show a tendency to radiate up into the cell body from 

 the axone hillock. 



2. Vital staining. — The probability that these fine granules are 

 mitochondria is made almost a certainly, for they may be seen under 

 the microscope to stain brilliantly with janus green. This dye was 



