MYXOSPORIDIA 311 



specific host-parasite relations, the reader is referred to Kudo 

 (1920). 



METHODS 



FresJi Material. As far as is possible, careful examination of 

 fresh material should be undertaken. In the case of a histozoic 

 myxosporidian which forms tumors, cysts or growths on the body 

 surface or in the internal organs of the host, note carefully their 

 location, form, size and color. By cutting or pricking the surface 

 of the lesion slightly, obtain a small amount of material which is 

 ordinarily composed of soft, homogeneous and milky white amor- 

 phous substance (the spores), and make an ordinary fresh prepa- 

 ration, by adding, if necessary, a drop or two of the physiological 

 salt solution. If the pathological changes observed on the host's 

 body are due to a myxosporidian infection, one would most likely 

 find a more or less large number of small refractile bodies, the 

 spores. 



In order to make an accurate observation of fresh spores, it 

 is, however, better to make hanging drop preparations which were 

 improved upon recently by Nemeczek (1926). In this, instead of 

 one coverglass, two are used ; the upper square one should be 

 big enough to cover the entire hollow of the slide and the lower 

 circular one small enough not to touch the margin of the hollow. 

 A small amount of the material is put on the center of a large 

 coverglass on the margin of which a line of vaseline is smeared, 

 cover the drop with a small circular coverglass and over the whole 

 place a depression slide so as not to allow the smaller coverglass 

 to come in contact with the margin of the hollow of the slide. 

 Press down slightly and make the larger coverglass adhere to the 

 slide. By carefully and quickly turning the preparation over, ex- 

 amine it coverglass up. This preparation is much better than 

 either an ordinary fresh preparation or hanging drop preparation, 

 since ( i ) the spores are free from mechanical pressure and sta- 

 tionary, and (2) the material is in a uniformly thin film instead 

 of a droplet as is always the case in a hanging drop preparation. 

 Hence, an oil immersion objective is easily applied for observa- 

 tion as well as for drawing with camera lucida. 



Make observation first with an objective with medium magnify- 

 ing power, and then with an oil immersion objective and a fairly 

 high-power ocular which combination would give a magnification 

 of at least 1000 times the natural size. Note the general appear- 



