88 The Microscope. 



Blood of Invektebrates. — Dr. Howell, in John Hopkins' 

 " Studies," describes the blood of the King crab, soft shell crab, and 

 a species of holothurian. In Limulus the blood is alkaline, quickly 

 coagulating. It contains fine albumens, which coagulate at difPerent 

 temperatures, but which all belong to the globulin group. They 

 resemble, but are not identical with paraglobulin. Coagulation in 

 the blood of Limulus results by the union of the corpuscles, and the 

 existence of a coagulative ferment has not yet been proved. The 

 fibrin is much like that of mammals in its solubility. Hsemocyanin 

 certainly contains copper. In Neptunus (Callinectes), the blood is 

 alkaline, but coagulates less quickly than that of Limulus. It con- 

 tains two albumens to be classed among the globulins, and the coao-u- 

 lation is more complete than in the King crab. The fibrin is very 

 difPerent from that of Limulus, and of it Dr. Howell says : "The 

 difference seems to me to be too wide to suppose any close relation- 

 ship between the two forms, especially as they have the same general 

 environments ; but until a series of similar observations are made on 

 the scorpion or some arachnid, we will not have sufiicient evidence 

 to make any just inferences with regard to the relationshijj of these 

 forms — that is, from the standpoint here assumed." In the holo- 

 thurian, which was identified as Thyonella gemmata, two kinds of 

 corpuscles were recognized: a red, hsemoglobin-bearing nucleated 

 oval form, and a spherical white nucleated form. Coagulation was 

 occasioned by the fusion of the white corpuscles, the red not taking 

 part in the formation of a coagulum except as they were entangled 

 in the meshes of the other. — Am. Naturalist. 



Bacteria in Drinking- Water. — Chas. E. Pellen, M. D., read 

 before the N. Y. Microscopical Society, March 16, .1886, an article 

 entitled " Bacteria in Drinking-Water." The writer calls attention 

 to the necessity of having good drinking-water, and cites many 

 instances where the water supply for ancient cities was obtained many 

 miles away. Then follows an account of the first observations with 

 the microscope and the discovery of the minute organisms now known 

 as bacteria. A short history of the bacterium is next carefully given, 

 with its power of development, its food, life, habits, times of quies- 

 cence and final death. Then follows a brief synopsis of cultivation 

 of the bacteria, as recommended by many investigators; after which 

 the bacteria in drinking-water are referred to and are considered 

 harmless to mankind, except as it may contain germs of typhoid fever 

 and cholera. 



