iyo SOME RECENT DEVELOPMENTS , 



ordinary cell, differing mainly in its more regular 

 arrangement. 



The changes that actually go on within the 



protoplasm of the cell-body in different phases of 



its activity have been studied most closely, and 



with the most definite results in secreting cells, 



either from special glands, such as the pancreas or 



salivary gland, or with still greater success in the 



epithelial cells lining the digestive stomach of 



certain insects. These secreting cells have their 



outer ends bathed in lymph, which diffuses from 



the neighbouring blood-vessels, while their inner 



ends form the bounding surface either of the gland 



or of the alimentary canal itself. The cells separate 



from the lymph certain products which they 



modify in various ways, and finally discharge at 



their free surface as the special secretion of the 



gland. Careful histological examination has shown 



that during rest the gland-cell enlarges, the special 



secretions accumulating in the meshes of the 



reticulum as a fluid or semi-fluid substance, often 



granular in appearance. During digestion, this 



secreted matter is discharged from the cells at 



their free surface, the meshes of the network 



becoming more or less completely emptied. As to 



the part played by the network itself the evidence 



is incomplete, but there is some reason to think 



that the secreted substance is formed in part at the 



expense of the reticulum. The discharge of the 



secretion does not necessarily involve the death of 



the cell, which may fill up again, time after time, 



with the secreted matter. 



