2538 Journal of Applied Microscopy 



gyri, the product of the length of the periphery by the thickness of the section 

 gave the area of that portion of the surface of the cerebellum included in each 

 individual section. Measured in this way the total surface area of the cere- 

 bellum studied was found to be 84.246 sq. mm. Of this total area 16.344 sq. 

 mm. were included in the free surface area, and 67.902 sq. mm. in the sur- 

 faces of the fissures. The relation of exposed and covered surfaces is not the 

 same in all parts of the cerebellum. While the cerebrum is from 8 to 9 times 

 heavier than the cerebellum, its surface area is only from 2.2 to 2.6 times greater. 

 The estimated number of Purkinje cells in the total surface area of the cere- 

 bellum studied was 14,237,<)74. R. p. 



CURRENT BACTERIOLOGICAL LITERATURE. 



H. W. CONN, Wesleyan University. 



Separates of Papers and Books on Bacteriology should be Sent for Review to H. W. Conn, 

 Wesleyan University, Middletown, Conn. 



Parker, Beyer, and Pothier. Yellow Fever The rapidity with which the etiology of 

 Inst. Bui. 1 3 of the Marine Hospital Service. ygUow fever has been solved since the 



close of the Spanish-American war is remarkable. Following close upon the 

 discovery of the mosquito as the means of conveying the disease comes the work 

 of the authors of this bulletin, who have discovered what appears to be the cause 

 of the disease. According to them the yellow fever is caused by an animal par- 

 asite, probably a sporozoan, that undergoes part of its life history in the mosquito. 

 Their evidence is not yet complete for they have hitherto failed to find anything 

 in the blood of the human patient that can be regarded as representing the 

 organism. But they find it in the body of mosquitoes that have fed upon the 

 blood of patients, prove that these mosquitoes can give the disease by biting, 

 show that other mosquitoes besides the Stegomyia do not contain the parasite 

 and that individuals of Stegomyia that have not fed upon yellow fever blood do 

 not contain the parasite or convey the disease, a series of facts that renders the 

 causal connection well nigh demonstrated. 



The methods which the authors adopt for studying the mosquito may be use- 

 ful for all students who are working upon the relation of mosquitos to human 

 diseases. The mosquito is placed alive in a small test tube and either killed 

 with tobacco smoke, or the test tube is simply inverted over a bottle of absolute 

 alcohol and the mosquito allowed to fall into it. After two hours in the alcohol 

 it is transferred to a watchglass, the legs pulled off and the wings cut close to 

 the body, and then the body is transferred to a change of absolute alcohol. 

 After two hours the insect is transferred to xylol and in half an hour placed in 

 the warm chamber of the paraffin bath. Here liquid paraffin is added, a few 

 drops at a time, until saturation, and then the insect transferred to melted paraf- 

 fin (52°). After an hour it is embedded. Serial sections are cut, usually 15 

 micra thick. The ribbons are floated by hot water on to a slide, flattened by 



