164 The Microscope. 



of preliminary training and practice must exist. The proper 

 manner of preparing tissues for examination is a tiling which 

 requires previous study as well as knack. In the rapid method 

 to which allusion has been made, the technique is simple enough 

 and can be acquired in a comparatively short time. Yet, those 

 who follow this subject closely will find that improved or novel 

 methods are being constantly suggested and introduced, many 

 of which are of doubtful worth. In those cases in which diseases 

 of the skin become the objects of prolonged research the student 

 will find the greatest necessity for preliminary training, not only 

 in all those various and complicated technical details relating to 

 hardening, section cutting, staining and mounting, but he will 

 be suddenly made aware of the value of a thorough knowledge 

 of histology. He will then appreciate the importance of a 

 knowledge of the minute structure of the skin and of its ap- 

 pendages. Further than this, he will also appreciate how useful 

 it is to be acquainted with elementary principles of pathology 

 as shown in the changes observable in tissues. For what will it 

 profit him to make a beautiful preparation of an excised portion 

 of diseased skin and to know that it is not normal, if he is incap- 

 able of interpreting the picture which is presented to his view ? 



I do not wish to be understood as advocating the necessity of 

 every practitioner becoming an expert in microscopy, but I do 

 uphold the absolute value of each one being capable of making 

 such examinations as ordinarily come up in practice, and which 

 are of immediate practical value not only in establishing a cor- 

 rect diagnosis, but in many instances in recognizing some process 

 which has not manifested itself by any clinical symptoms. 



In skin disease the value of microscopic examination cannot 

 be overestimated. In mixed diseases, especially in which one 

 masks the other, a very cursory microscopical examination will 

 very often demonstrate the true status of affairs. Where doubt 

 exists we have, as a rule, an easy, rapid and certain method of 

 determining the true condition. I might cite, as an example, a 

 case which I was called upon to treat some time ago. It was 

 one of pustular eczema of the scalp, of an apparently aberrant 

 form. Certain patches were round, covered with thick crusts, 

 the hairs being short. A microscopic examination demonstrated 

 the presence of tinea tonsurans at these spots. Again, in a case 

 of pustular eczema of the scalj) closely simulating favus, a mic- 



