Journal of Applied Microscopy. 



263 



and did the abdominal position, normal to the ovary, so influence the cells of the 

 organs as to lead to an attempt to develop ova after it had acquired dis- 

 tinct male characteristics ? Did the ova come from any of the germ cells as they 

 were then developed, or from some indifferent ones, which when subjected to 

 conditions normal to the ovary began to develop into ova ? 



These are questions which arise and are difficult to answer, but suggest a pos- 

 sibility of the influence of environment on determining the line of development 

 in an important matter and at a relatively late stage in embryonic life. I should 

 be glad to know if any reader has observed a similar state of this organ in any 

 animal, and if so what microscopic testimony it gives on this point. The tissues 

 were hardened in four per cent, formalin with fifty per cent, alcohol, and gave 

 good results both as to stain and preservation. 



Edith J. Claypole. 

 Wellesley College. 



A Simple Gasometer for Fermentation Tubes. 



Since Theobald Smith's* work on the fermentation tube, this piece of appa- 

 ratus has become quite generally used and is a valuable agent in the study and 

 differentiation of bacteria. 



Where gas is formed it is desirable that the total amount of gas, as well as the 

 relative proportion of the constituents, be determined. Graduations on the closed 

 arm, as in the case of Einhorn's pattern, add to the expense more than is war- 

 ranted by the degree of accuracy required, and therefore for bacteriological work 



the tubes are ungraduated. The 

 gas ratios are generally deter- 

 mined by measuring with an 

 inch or centimeter rule and cal- 

 culating the per cent, in terms 

 of the length of the closed arm. 

 Inasmuch as the tubes usually 

 vary considerably in size, the 

 calculations often become quite 

 time-consuming. To overcome 

 this, the piece of apparatus 

 represented in the accompany- 

 ing figure was devised, and has 

 been used in these laboratories 

 for some time. 

 It consists of a piece of triple-plated tin cut in the shape indicated, about 

 eight inches long, six inches wide at one end and two inches at the other. The 

 wide end is long enough to accommodate the largest fermentation tubes, while 

 the narrow end is sufficiently short for the smallest. About a half inch of the 



* Wilder Quarter Century Book, p. 187. 



