1878.] Dr. H. Watney on Minute Anatomy of the Thymus. 369 



sounds which have hitherto been inaudible by the mere operation of 

 sonorous vibrations upon the conducting power of matter. 



My warmest thanks are due to Mr. W. H. Preece, electrician to the 

 Post Office, for his appreciation of the importance of the facts I have 

 stated, and for his kind counsel and aid in the preparation of this 

 paper. 



I do uot intend to take out a patent, as the facts I have mentioned 

 belong more to the domain of discovery than invention. No doubt 

 inventors will ere long improve on the form and materials employed. 

 I have already my reward in being allowed to submit my researches to 

 the Royal Society, 



II. " Note on the Minute Anatomy of the Thymus." By Her- 

 bert Watney, M.A., M.D. Cantab. Communicated by 

 Dr. Klein, F.R.S. Received April 8, 1878. 



The thymus is composed of lobes, lobules, and follicles. 



Each follicle consists of a cortical and a medullary portion ; the 

 medullary parts of two neighbouring follicles are often united ; and 

 at one point, therefore, the medullary portion may extend through the 

 cortex of the follicle ; in some follicles the medullary portion may be 

 found in the form of two or more islands situated in the interior of the 

 follicle. 



The follicle is composed (a) of a reticulum of nucleated cells, and (b) 

 of cells ; the reticulum forms an adventitia to the blood-vessels. 



The cells forming the reticulum in the cortical part of the follicle 

 consist of a disk-shaped nucleus, a cell body very little larger than 

 the nucleus, and of very long, fine, branching processes. 



The reticulum of the medullary portion is composed of cells with 

 coarse, short processes ; the body of the cell is more than twice, or 

 even three times, as large as the nucleus, and contains one, or at 

 times, two nuclei ; in places, large protoplasmic masses are met with, 

 forming part of the reticulum composed of two or three cells united 

 together. There are also found in the medullary portions, in certain 

 states of the thymus, connective tissue trabecule. 



The cells are of four kinds : — 



(1.) Small cells, resembling the lymph cells of a follicle of a 

 lymphatic gland. Staining fluids act differently on these cells in the 

 cortical and in the medullary parts of the follicle. 



(2.) Large granular cells of various sizes ; many of them have long 

 processes by which, in some cases, they are attached to the trabecules 

 and to the blood-vessels : these cells contain one or two nuclei, and 

 help to form (partly by a process of vacuolation) the concentric cor- 

 puscles of the thymus. 



