214 The Mecroscope. 



months to differentiate a periosteum by a condensation of the 

 connective tissue into a membrane in the case of the maxella and 

 bones of that class — that is, groups of osteoblasts are seen arranged 

 together more or less regularly, but independent of the periosteum. 

 At first the specialized cells are found in a double layer, but 

 later on they may be seen at the termini of the trabeculae. As the 

 osteoblasts build themselves into the wall of forming bone, new 

 layers take their place. When each osteoblast, by secreting its 

 calco-spherule, completes its life work as a bone builder, it becomes 

 a bone cell. The osteoblast is undoubtedly derived from the 

 corpuscles of the blood. 



Nomenclature of Pathogenic Organisms. — The Medical and 

 Surgical Reporter gives the following nomenclature of pathogenic 

 micro-organisms, according to the accepted recent definitions of Dr. 

 J. Schroeter: Micrococcus vaccince (Cohn), the active portion of 

 vaccine lymph ; Micrococcus decalrans (Cohn), produces baldness ; 

 Streptococcus erysipelas (Koch), induces erysipelas ; Streptococcus 

 diphthereticus, active in diphtheria ; Hyalococcus pneumonice, 

 present in croupous pneumonia ; Hyalococcus heinzii, causes the 

 gregarina of hair ; Bacillus anthracis (Cohn), produces anthrax ; 

 Bacillus tuberculosis (Koch), in phthisis; Bacillus leprae (Hansen), 

 in leprosy ; Bacillus typhus (Eberth), in typhoid fever ; Microspora 

 comma (Koch), induces Asiatic cholera ; Microspora finkleri (Koch), 

 present in cholera nostras ; Cladothrix foersteri (Cohn), found in 

 diseases of the lachrymal ducts. 



House-Flies as Carriers of Tuberculosis Contagion. — Spill- 

 man and Haushalter have recently reported to the Academy of 

 Sciences, (Paris, Session August 16th,) their investigations as to the 

 possibility of " contagion " (bacillus) of tuberculosis being carried 

 by house-flies, and the results make it extremely probable that these 

 pests of our dwelling-houses and hospital wards may have much to 

 do with the propogation and dissemination of such contagion. 



These investigations included repeated examinations made of 

 the excrements and intestines of flies that had fed on the con tents 

 of the spit-cups of consumptive patients; in both they found abund- 

 ance of tubercle bacilli. They also found the same bacilli in the 

 dried excrements of flies scraped from the windows and walls of 

 rooms occupied by phthisical patients. The experimenters show 

 how easily such germs may be disseminated by the dried excre- 

 ments, or even by the dessicated pulverulent remains of the bodies 



