: Monthly Micr ical 
234 NOTES AND MEMORANDA. Journal, Oct. 1, 11D. 
in the heated liquid, because the germs might be able to sustain a 
much greater amount of heat in a gaseous form than in a liquid form. 
Dr. Bastian said the flasks were frequently shaken. Professor Tyndall 
thought that was not enough. Dr. Bastian would have to repeat his 
experiments before they would be of any value to anybody who 
required strict proof. Dr. Bastian said that what he maintains is, so 
far as our present state of knowledge goes, the evidence is in favour 
of spontaneous generation. The Chairman said, with reference to 
all these experiments with heat, it seemed to him that the analogy of 
albumen, which, after it had been exposed to the action of the digestive © 
juice, was no longer amenable to the action of boiling water, was a 
great light. It was possible that the limit of endurance of heat by 
vitalized albumen had not been gained. Peptone was a highly complex 
organized albumen, and nevertheless it was not acted upon by heat at 
all. Taking a large view of the whole question, he was rather preju- 
diced against the theory of spontaneous generation. 
The Scientific Exploration of the ‘Porcupine’—The copy of the 
‘Proceedings of the Royal Society’ containing Dr. Carpenter’s valu- 
able report on the above, has at length appeared, and from its great 
length and the many valuable appendices it contains, deserves to be 
in the possession of every naturalist. It extends over one hundred 
pages, occupying a whole number of ‘ Proceedings.’ It would be 
impossible to give anything like a review of this paper, which is of 
the great length we have mentioned, and we can only hope that our 
readers will procure the copy of the ‘ Proceedings’* for themselves. 
The first part deals with the apparatus, and it shows us that the 
author has paid attention to even the most adverse criticism of his 
earlier voyage, and has on this occasion taken care to have all the 
apparatus constructed upon the most thoroughly scientific principles. 
It is greatly to be regretted, though, that the electric sounding appa- 
ratus was found not to work sufficiently well at sea to enable Dr. 
Carpenter and his assistants toemploy it. The details are singularly 
minute, and the appended reports by W. Lant Carpenter, B.A., B.Sc., 
Dr. Frankland, F.R.S., and Mr. David Forbes, F.R.S., though short, 
are of an excellent character. 
NOTES AND MEMORANDA. 
The Focal Length of Microscopic Objectives.—Mr. C. R. Cross 
has ably discussed this subject in an American magazine called the 
‘Franklin Journal, He remarks :—“ The investigation of which the 
present article is a summary, was undertaken in order to see if some 
reliable method of measuring the focal length of microscope objectives 
could not be found. 'The importance of such a method will be appa- 
rent to all who have had occasion to make use of objectives by different 
* No. 121, 
