174 THE MICROSCOPE. Nov. 



Tripethelium. — This is a lichen but the method of manipu- 

 lating it is applicable to a very numerous class found on bark. 

 This specimen is found frequently on beech bark. The bark 

 affected will have a number of raised black spots. Under a low 

 power these spots will be found to be little elevated warts with 

 often a little hole (astiole) in the center. On the outer bark 

 nothing worthy of a high power can be found. Shave off the 

 upper surface of a small piece and cut down into the inn'^r bark. 

 Then where the warts were little spots will be seen. Dig out 

 one of these spots ; transfer to a drop of potassium hydrate on a 

 glass slip ; mash and spread out with a spatula ; then cover and 

 examine with a quarter objective. The contents are hyaline nnd 

 glassy white. Numerous apothecia each containing eight spores 

 will be sfen. The spores are long, glassy and acicular and 

 eight locular and each division of' the spore is marked with a 

 double convex lens shaped marking. The method here de- 

 scribed is applicable to many bark lichens all the Verrucaria 

 and also to many of the Pyrenomycetes. Many of the fungi 

 which affect bark are superficial and need but to be scraped off 

 to be seen. 



Blood Showing the Effect of Tobacco.— The effect of the 

 excessive use of tobacco can be clearly demonstrated by the ex- 

 amination of a properly spread slide of the patients blood. In 

 such cases. red corpuscles w^ill be found to be crenated, that is 

 the corpuscle instead of possessing the absolute regularity of 

 margin noticed in health Avill present a series of scallops some 

 whit irregular in their distribution. A few such crenated cor- 

 puscles, in the proportion of one to three hundred and fifty oc- 

 cur in normal health but in tobacco blood the ratio is 

 sometimes as high one degenerated corpuscle to ten healthy 

 ones, and often attains a much larger proportion. Opium and 

 other narcotics produce the same result. Nervous excitement, 

 certain diseases will frequently produce crenation and the blood 

 in dense urine will often be found in this state. Where the 

 patient is otherwise healthy a number of crenated corpuscle? in 

 his blool, as above indicated, may safely be ascribed to the ex- 

 cessive use of tobacco, opium or some narcotic and it is then', 

 high, time to stop their use. 



