42 THE AMERICAN MONTHLY [Feb 
a serum having a potency of 1:10. If too little serum was 
given, the course of the disease was slowed, the animal 
improved for a time and then suffered a relapse, and died 
in from thirteen to seventeen days. The serum also pro- 
duced immunity, but of only ten to fourteen days dura- 
tion. } 
An immunity lasting three weeks was conferred by in- 
oculating a monkey with an agar-agar culture heated to 
60 °C. If too large a dose of such a culture was given, 
however, the animal was enfeebled and remained suscep- 
tible. Of Yersin’s serum, which is prepared by immuniz- 
ing horses in the usual manner to toxins and cultures of 
the bacillus, 5 c. em. doses have been found to confer an 
immunity lasting for about a fortnight. Larger doses con- 
fer a longer immunity. For the treatment of the devel- 
oped disease, enormous doses of 50 and even 100 c. cm. 
seem to be necessary to produce the desired results, evi- 
dently indicating that the serums thus far obtained are 
weak. 
BIOLOGICAL NOTES. 
L. H. PAMMEL. 
AUTO-INTOXICATION AND SpYRoGyRA.—Ina recent num- 
ber of the American Journal of the Medical Sciences, Dr. 
Klingmann makes some interesting statements with ref- 
erence to auto-intoxication and toxic states of blood. He 
has experimented with protozow and algex, which were 
treated with various toxic substances. The alga used was 
Spirogyra. After describing briefly the normal peculiar- 
ities of Spirogyra, he shows that toxic substances like 
those produced in certain contagious diseases, and those 
following epilepsy, produced certain pathological changes 
in the Spirogyra. 
‘‘The water which is used for diluting the blood is test- 
ed by placing a few threads of Spirogyra in a glass dish 
