The Microscope. 235 



wound upon herself. The carpet where the dead man lay was 

 saturated with blood. According to the theory of the prosecu- 

 tion, the blood on the pillow was his also. Dr. Piper put the 

 section of the pillow with blood upon it under the microscope, 

 and drew on a cardboard the shape of the corpuscles, enlarged 

 about two thousand diameters. He then put the blood on the 

 carpet under the microscope in the same way. The comparison 

 settled the question at once. 



The blood corpuscles were as different as day and night, 

 and sustained the woman's account of the shooting. She was 

 acquitted on that and other evidence. 



As between human blood and dog's blood, the microscope 

 enables the expert to determine precisely whether a specimen 

 is from a human being or a dog. But it is impossible to deter- 

 mine between human blood and a hog's blood. — Scientific 

 American. 



PERMANENT MOUNTING OF TRACHEAE OF INSECTS. 



F. T. HAZLEWOOD. 



I have succeeded in a very simple way in mounting per- 

 manently the tracheal system of insects. I dissect out the soft 

 parts and spread them on a glass slide of the usual size; let 

 them dry perfectly ; then with pencil-brush give them a good 

 coating of collodion, after which I melt a little hard, pure bal- 

 sam in a test tube and put it on the object with a cover glass 

 applied at once. This is, so far as I know, a new method. It is 

 remarkable for its results. The intestines, the ganglia, and the 

 brain are perfectly magnificent. The intestine makes thus one 

 of the most beautiful objects for dark-ground illumination. The 

 brain shows the most abundant ramifications of the trachea, 

 especially in the immense parallel branches in the rods of the 

 eyes. The ganglia can be floated on a cover glass, dried, and 

 mounted in this way. The entire process is simple and easy, 

 and gives the most satisfactory results. There are many points 

 of histological interest in the brain which are thus demonstrated. 



THE JOURNALS FOR SEPTEMBER. 



The Microscope contains in a series of detached articles a 

 pretty full report of the Cleveland meeting of the American 



