650 Journal of Comparative Neurology and Psychology. 



to a sharp point. If there were no bend in the small strip it would 

 split in its natural line of cleavage along the course of its fibers. 

 We can correct the curve by applying our forces at a point very close 

 to the separating part and keeping them close all the way down the 

 lx)ard. The above are simple facts kno\^ni to eveiybody, and what 

 I Avish to impress upon the reader is that the laws hold good when 

 applied to brain dissection. The brain dissection which I advocate 

 is an application of these laws. We must find the line of cleavage 

 and properly apply the forces so that there will be an equal pressure 

 and equal resistance on each side, and the filjers will not be forced 

 into a false separation by breakage. Of course we know that if there 

 are intercrossing fibers which run singly or in very fine bundles, 

 there must be a certain amount of breakage. This cannot be avoided, 

 but our purpose in gi-oss dissection is to arrive at a knowledge of the 

 macroscopic anatomy with a view of helping the microscope, and also 

 for practical surgical purposes. If we know that there is a large 

 bundle running from one place to another, even though we are not 

 aware of its function, we do at least know that it is important on 

 account of its size, and we assume that it must be doing some great 

 and necessary work. 



If we wish to dissect deep structures at once, it is best to shell off 

 the superficial fibers with our fingers. For this we must use a pair 

 of thin rubber gloves so that we may not injure the deeper struc- 

 tures with our nails. Those superficial fibers which are less easily 

 shelled off will be found to be connected with deeper structures in 

 well defined bundles. In this shelling also it is important to keep 

 constantly in mind the knowledge which we gain in consideration 

 of the simple process of splitting wood, referred to above. Finally, 

 when we have dissected a number of brains and have compared the 

 microscopic findings with the dissected fibers, we gain a very accurate 

 knowledge of the texture and behavior of brain substance which goes 

 with its microscopic appearance. It will not be convenient for us 

 to make a microscopic preparation of everything we dissect, but we 

 may have access to such things already made, and by this comparison 

 be able to tell almost exactly what some of its predominating micro- 

 scopic characters are without microscopic examination. 



