106 CARNEGIE INSTITUTION OF WASHINGTON. 



factory hypothesis as to their significance, and the fact that they 

 actually penetrate the egg, warrant a thorough investigation before 

 they are eliminated as theoretical bearers of hereditary characteristics. 



In connection with an investigation on the seminal cells of the 

 opossum. Dr. Duesberg has extended his studies to the complex inter- 

 stitial cells which are present in large numbers in the testicle of this 

 animal. He finds that these cells contain either one or two nuclei, an 

 idiosome with, two or more centrioles, an apparatus of Golgi, some fat, 

 crystalloids of two types, and chondriosomes. They exhibit, however, 

 two especially noteworthy features. Due, as the author thinks, to 

 the conditions of fixation, the chondriosomes are modified so as to 

 form a huge framework which bears a striking resemblance to some 

 types of Golgi's apparatus, or, perhaps, a trophospongial net. This 

 framework is not found in all parts of the cell-body, but leaves free the 

 periphery and a space in the immediate vicinity of the nucleus, which 

 might safely be construed as the idiosome. The second feature is the 

 presence of an intracellular substance which appears to be an accumula- 

 tion of a granular or amorphous secretion product and which, owing 

 to its staining properties, can be followed on the preparations into the 

 intercellular spaces and finally into the vessels. This constitutes one 

 of the clearest instances in which the secretion product of an endocrin 

 gland can be actually followed from the glandular cell into the vascular 

 system. 



An important study in the phenomena associated with cell degenera- 

 tion has been made by Professor W. H. Lewis. Using explants from 

 chick embryos, he has cultivated fibroblasts in vitro and has observed 

 the occurrence and behavior of certain granules and vacuoles which 

 apparently form Vv-ithin them as waste products, and which he regards 

 as a part of the process of cell degeneration. The living fibroblasts 

 were observed over periods of one to three days, in most cases with the 

 use of neutral red and Janus black No. 2. The neutral red dye is 

 rapidly taken up by the vacuoles and granules, whereas the Janus 

 black stains only the mitochondria. In this way he had a differential 

 test which enabled him to show that the granules and vacuoles bear no 

 relation to the mitochondria, with the exception that, as the number of 

 granules increased, the mitochondria changed from threads and rods 

 to granules and vesicles, and, in cases of extreme vacuolization, became 

 lodged between the vacuoles. Degeneration granules are few in num- 

 ber in normal cells, but abundant in cells showing extensive vacuoliza- 

 tion. They practically never occur in vigorous young fibroblasts, but 

 increase progressively with the age of the culture. Their size varies 

 from extremely minute, and probably ultra-microscopic, to half the 

 diameter of the nucleolus. After there has been a considerable accumu- 

 lation of these granules, fluid vacuoles begin to develop around them. 

 These also vary in size, and their shape is constantly altering with 



