Ii6 HOW TO WORK 



elementary fibre of muscle may be divided longitudinally into 3. 

 number of minute fibrillcz, arranged parallel to each other ; while 

 under other circumstances it can be separated transversely into a 

 pile of small disks, or into a number of small elementary particles of 

 definite form and size, by the connection of which to the contiguous 

 particles, fibrillce or disks are produced, according as the particles 

 adhere to each other most intimately by their sides or by their ends. 

 I might adduce many other instances of the necessity of studying 

 the general character of tissues before any minute examination of the 

 individual structures is attempted, but this is sufficient. 



211. On Demonstrating the Anatomical Peculiarities of Tissues. 

 Now, some observers who have not sufficiently considered the 

 different characters of the elementary structures of which most of 

 the organs of the body are composed, have strongly objected to 

 what they term methods of preparation, asserting that by these pro- 

 cesses, structures are even formed artificially which have no real 

 existence in the natural state of the part. For this view there is 

 some reason. Doubtless, from the examination of a dead tissue we 

 can form but an imperfect conception of the beauty of its elementary 

 parts, and their wonderful adaptation to the office they are designed 

 to perform in the animal economy ; neither can we form an idea of 

 the changes taking place during life ; and we must remember that 

 there is no known fluid in which we can immerse a specimen for ex- 

 amination, which possesses the precise characters of that which 

 bathes the tissue during its lifetime. Serum may, perhaps, be the 

 nearest approach to such a fluid, but there is reason to believe that 

 this differs from the fluid surrounding the primitive particles almost 

 as much as some artificial media which have been proved by 

 experience to give very satisfactory results. On the other hand it 

 is, however, to be remarked that those who raise objections to 

 the preparation of tissues have not satisfactorily demonstrated 

 that by the plan they follow, many of the structures which we 

 see after death in v/ater, serum, and other simple fluids really 

 have a precisely similar appearance during life, and it is more 

 than probable that many of the more delicate tissues have never 

 been seen by any one in the condition in which they exist during 

 life. I believe that the amount of opacity which is absolutely neces- 

 sary for seeing some of these is quite inconsistent with their natural 

 condition, and is the result of a change which has never been fully 

 appreciated, though, perhaps, some idea of its nature may be formed 

 by considering the characters of fibrin in the circulating blood, and 

 fibrin removed from the organism and coagulated, or those of albu- 

 men dissolved in the serum, coagulated but transparent in many of 



