74 MANUAL OF HISTOLOGY. 



way of showing it consists in making a section through fat tis- 

 sue that has been hardened in alcohol or Mueller's fluid, or both. 

 The phenomena will, in this way, be well shown. After im- 

 mersion in an acid solution, it will be seen that the fatty acids 

 crystallize in the centre of the sac. 



The nature of the evidence that fat corpuscles are really the 

 altered corpuscles of the fibrous tissues is as follows : They 

 occupy the same position, being in rows, between the bundles, 

 just as the other corpuscles that we have mentioned ; a few oil 

 drops at first appear, then others, until finally they coalesce 

 into a single large drop, which fills the corpuscle ; if fat tissue 

 be pressed, and the oil escapes, the walls of the fat-corpuscles 

 collapse, and then the flattened nuclei may be observed on the 

 side of the cell-body. 



Waldeyer believes that there is a peculiar corpuscle, three 

 to five times the size of the lymphoid, and roundish, which is 

 especially prone to take up fat, and be converted into a fat- 

 corpuscle. 



This body, known as the plasma cell, is the second element 

 that forms the fat -cell. The change is said to occur only occa- 

 sionally, and under favorable conditions of alimentation 

 (Klein). 



The same author states that there is also a third way in 

 which fat is formed : In many parts of serous membranes, espe- 

 cially in connection with the large vessels, there appear " no- 

 dules or cords, which are made up of multiplying connective- 

 tissue cells." The cells increase, the matrix is converted into a 

 network, lymph-corpuscles appear, the tissue is supplied with 

 arteries, veins, and capillaries, and resembles lymphatic tissue. 

 Sometimes these structures persist as they are ; in other cases 

 they are converted into fat -tissue. 



Eanvier recommends the following plan of demonstrating 

 fat-tissue : He injects beneath the skin a weak solution of os- 

 mic acid (1-1000), The connective-tissue corpuscles may be 

 seen to be more or less filled with oil-globules. 



The property of taking up oil is not peculiar to these cor- 

 puscles already described, but belongs, physiologically, to the 

 liver, to adult cartilage, the glandular elements of the female 

 breast during lactation, and the glandular epithelium of the 

 sebaceous glands. 



Inter muscular tissue. It has been claimed by some that 



